Co přináší savčí matka svému potomstvu (kromě výživy v děloze) OOCYT /^~^^^^- pólová tělíska MATERNALNI DĚDIČNOST ^ EPIGENETICKA INFORMACE (RNA, proteiny aj.) metylace DNA a modifikace jako první informace GENETICKÁ A STRUKTURNÍ chromatinu oocytu vyvíjející se zygoty INFORMACE jaderný genom samicí gamety, buněčné struktury (př. mitochondrie) Raný vývoj savčího embrya ICM=inner cell mass (vlastní embryo) embryonic stem EG = embryonic cells (in vitro) germ cells (in vitro) TE=trofektoderm (-placenta) ta blastocysta všechny somatické buňky (in vivo) pluripotentní PGC = primordial buňky epiblastu germ cells EPIGENETICKE REPROGRAMOVANI V PRŮBĚHU SAVČÍHO VÝVOJE zygota 5metCytosin H3K27met3 H3K4met3 5metCytosin H3K9met2 embryo trofektoderm placenta maternální pronukleus 5metCytosin H3K9met2 H3K27met3 paternální pronukleus j,5metCytosin j, 5metCytosin ICM blastocysta t 5metCytosin f H3K9met2 f H3K27met3 Preformace = dědičnost preformovaných zárodečných buněčných determinant (Drosophila, Caenorhabditis) Epigeneze = specifikace buněk zárodečné dráhy, kde skupina potenciálně ekvivalentních pluripotentních buněk získá své poslání v reakci na induktivní signály, zatímco zbývající buňky se stávají somatickými (myš, člověk, rostliny) U D. melanoaaster isou orekurzorv zárodečných buněk pólové buňky v posteriorní části syncytia, transkripční umlčování závisí na RNA kódované genem Pgc C. eíegans D. melanogaster Pole cells (H3K9 methylation) M. musculus PGC Pie-1 pgc: Polar granule component Blimpl Zárodečná linie C. elegans je specifikována po prvním buněčném dělení zygoty expresí genu Pie1 (transkripční umlčování), druhá buňka se stává somatickou. U M. musculus časné prekurzory zárodečných buněk vznikají po expresi genu Blimpl, který iniciuje transkripční umlčování v těchto buňkách. KLONOVÁNÍ: TRANSPLANTACE JADER Klonování savců vede k poruchám imprintingu konvenční fertilizace klonování přenosem jádra normální aberantní metylace embryogenéze i embryogenéze „Fatherless" Kaguya (Nature 428: 860, 2004) vyřazení imprintovaných genů může vést k vývinu plodné myši partenogenetického původu B G 9 12 TB HB Donor stage 20 26 40 66 Hours after fertilization FT 144 The Survival of Xenopus Nuclear Transfer Embryos Decreases as Donor Nuclei Are Taken from More Specialized Donor Cells Donor stage abbreviations: (B) blastula; (G) gastrula; (N) neurula; (TB) tail bud; (HB) heart beat; (ST) swimming tadpole; (FT) feeding tadpole. NORMÁLNI VÝVOJ REPRODUKČNÍ KLONOVÁNÍ TERAPEUTICKÉ KLONOVÁNÍ sperm (1 n) oocyte (1 n) \ / fertilization/IVF \ / zygote (2n) blastocyst I O I implantation in uterus adult cell (2n) enucleated oocyte patient's cell (2n) enucleated ooc \ / nuclear transfer NT embryo (2n) J Q I uterine transfer into surrogate mother I CViv cloned mouse NT blastocyst \ / t O t m m m ^ ^ ntES cells / I \ in vitro differentiation mm mm blood cell muscle cells neurons EPIGENETIKA A LIDSKÉ CHOROBY eckwith-Wiedemann Parentální imprinting růstových faktorů: převaha otce (chrl 1) Prader-Willi Parentální imprinting genového shluku (ch15): paternální delece Martin-Bell X-chromosom vázané mentální retardace: metylace CGG Russel-Silver převaha matky (chr7) Angelman maternální delece Rett mC-vazebný protein EPIGENETIKA A LIDSKÉ CHOROBY [1] PORUCHY IMPRINTINGU Beckwith-Wiedemannův syndrom Russell-Silverův syndrom Angelmanův syndrom Prader-Williův syndrom Pseudohypoparatyreóza [2] PORUCHY METYLACE DNA Imunodeficience ICF syndrom Metyléntetrahydrofolát reduktáza Rettův syndrom [3] PORUCHY STRUKTURY CHROMATINU Schimkeho imunoskeletální dysplázie Rubinstein-Taybiho syndrom Facioscapulohumerální svalová dystrofie [4] X-VÁZANÉ EPIGENETICKÉ PORUCHY Martin-Bellův syndrom Mentální retardace vázaná na a-thalasemii Cofflin-Lowryho syndrom [5] NÁDOROVÉ BUJENÍ Wilmsův renální tumor EPIGENETIKA A LIDSKÉ CHOROBY [1] PORUCHY IMPRINTINGU Beckwith-Wiedemannův syndrom Russell-Silverův syndrom Angelmanův syndrom Prader-Williův syndrom Pseudohypoparatyreóza [2] PORUCHY METYLACE DNA Imunodeficience ICF syndrom Metyléntetrahydrofolát reduktáza Rettův syndrom [3] PORUCHY STRUKTURY CHROMATINU Schimkeho imunoskeletální dysplázie Rubinstein-Taybiho syndrom Facioscapulohumerální svalová dystrofie [4] X-VÁZANÉ EPIGENETICKÉ PORUCHY Martin-Bellův syndrom Mentální retardace vázaná na a-thalasemii Cofflin-Lowryho syndrom [5] NÁDOROVÉ BUJENÍ Wilmsův renální tumor Chybný imprint P-alely (insulinový růstový faktor) či M-alely (růst suprimující H19-RNA) vede k Beckwith-Wi^d^/iannověsymJromu {tinsb příběh Otesánka) Russell-Silverův syndrom: maternální disomie chromosomu 7 růstová retardace in uter o postnatální růstová deficience asymetrický dwarfismus POTLAČUJE MATKA VÝVIN SVÝCH DĚTÍ ? aneb příběh Palečka David Haig ... teorie parentálního konfliktu (A. Russell 1954, H. K. Silver 1953) maternal deletion paternal UPD imprint defect mutations in UBE3A (a) ANGELMAN SYNDROME PRADER-WILLI SYNDROME (b) paternal deletion cause: genetic epigenetic mixed maternal UPD Angelmanův a Prader-Williův syndrom mohou být způsobeny genetickými nebo epigenetickými poruchami dvou imprintovaných genových shluků p11 -13 na chromozomu 15 li li genetic maternální dizoimie Prader-Williův a Angel manů v syndrom jsou komplexní neurovegetativní choroby, které souvisejí s imprintingem genového shluku (jsou naznačeny vždy dva lokusy) na chromozomu 15. Aktivní (světlé symboly) a imprintované (tmavé symboly) alely se nacházejí na paternálním (p) i maternálním (m) chromozomu. Nejčastější příčinou lehčího PW syndromu jsou delece na paternálním chromozomu a maternální dizomie. Těžší AS je obvykle způsoben maternální deleci paternální dizomií nebo biparentální expresí. Pseudohypoparatyreóza (PHP) Porucha funkce parathyroidního hormonu (příštítných tělísek), vede ke změně metabolismu vápníku a fosfátu, řada vývojových defektů. Odpovědný je gen GNAS1 (guanin-nukleotid-vazebný protein) má tři alternativní exony, které jsou sestřihovány do různých exonů tvořících odlišné transkripty. Odlišná metylace v okolí těchto exonů vede k exkluzivní expresi maternální alelv jednoho exonu a dvou paternálních exonů. Syndrom choroby může být způsoben poruchou imprintingu - např. uniparentální disomií, de novo metylací, ... B EPIGENETIKA A LIDSKÉ CHOROBY [1] PORUCHY IMPRINTINGU Beckwith-Wiedemannův syndrom Russell-Silverův syndrom Angelmanův syndrom Prader-Williův syndrom Pseudohypoparatyreóza [2] PORUCHY METYLACE DNA Imunodeficience ICF syndrom Metyléntetrahydrofolát reduktáza Rettův syndrom [3] PORUCHY STRUKTURY CHROMATINU Schimkeho imunoskeletální dysplázie Rubinstein-Taybiho syndrom Facioscapulohumerální svalová dystrofie [4] X-VÁZANÉ EPIGENETICKÉ PORUCHY Martin-Bellův syndrom Mentální retardace vázaná na a-thalasemii Cofflin-Lowryho syndrom [5] NÁDOROVÉ BUJENÍ Wilmsův renální tumor ICF syndrome From Wikipedia, the free encyclopedia ICF syndrome (or Immunodeficiency, centromere instability mid facial anomalies syndrome) is a very rare autosomal recessive immune disorder. Genetics [ ICF syndrome can be caused by a mutation in the DNA-rnethyltransferase-3b (Dnrnf3b) gene.'1' Presentation It is characterized by variable reductions in serum immunoglobulin levels which cause most ICF patients to succumb to infectious diseases before adulthood. ICF syndr patients exhibit facial anomalies which include hypertelorism, low-set ears, epicanthal folds and microglossia. Unaffected Carrier Carrier Affected son daughter son daughter Chromosomal abnormalities in metaphasic and interphasic cells of ICF patients: dual-color FISH was performed with chromosome 1 (green) and chromosome 16 (red) paint probes. Chromosomes and nuclei are counterstained with DAPI (blue), (a) and (c) show chromosomal abnormalities and micronuclei involving specifically chromosome 1, as frequently observed in the ICF1 and 1CF3 cell lines, (b) and (d) show chromosomal abnormalities and micronuclei involving both chromosomes 1 and 16, as frequently observed in the ICF2 cell line. - imunodeficience, karyologická nestabilita centromer, kraniofaciální defekty, psychomotorické retardace - mutace metvltransferázového genu Dnmt3b vede k hypometylaci subcentromerických repeticí (heterochromatinu) na chromozomu 1, 9 a 16 - není jasné, proč ztráta funkce široce exprimované de novo metyltransferázy ovlivňuje specifické repetitivní DNA sekvence Metyléntetrahydrofolát reduktáza (MTHFR) a mentální retardace - zásadní reakce v metvlačním metabolismu: přenos metylové skupiny z metvléntetrahvdrofolátu přes homocvstein a metionin, konečným donorem metylové skupiny pro všechny metyltransferázy je S-adenosyl metionin (SAM) - deficience MTHFR způsobuje vzácnou autosomálně-recesivní mentální poruchu - gen MTHFR je polymorfní, může se projevit i nízká folátová dieta, následkem mohou být i projevy Angelmanova syndromu METYLACE DNA, CHROMOSOM X a RETTŮV SYNDROM It is now known that RS can occur in males, but is usually lethal, causing miscarriage, stillbirth or early death. First described by Dr. Andreas Rett, RS received worldwide recognition following a paper by Dr. Bengt Hagberg and colleagues in 1983. Mutace v X-vázaném genu kódujícím mC-yazebný protein vede těžké mentálně-fyzicke^ poruše http://www.rettangels.org/ We have identified proteins that mediate repression by binding to methylated DNAj and are studying their biology. The founding member of the family is MeCP2, which represses transcription of methylated genes by recruitment of a corepressor complex that contains histone deacetylases. The MECP2 gene is clinically important as mutations within it are the primary cause of Rett Syndrome, a severe inherited neurological disorder that affects girls. EPIGENETIKA A LIDSKÉ CHOROBY [1] PORUCHY IMPRINTINGU Becwith-Wiedemannův syndrom Russell-Silverův syndrom Angelmanův syndrom Prader-Williův syndrom Pseudohypoparatyreóza [2] PORUCHY METYLACE DNA Imunodeficience ICF syndrom Metyléntetrahydrofolát reduktáza Rettův syndrom [3] PORUCHY STRUKTURY CHROMATINU Schimkeho imunoskeletální dysplázie Rubinstein-Taybiho syndrom Facioscapulohumerální svalová dystrofie [4] X-VÁZANÉ EPIGENETICKÉ PORUCHY Martin-Bellův syndrom Mentální retardace vázaná na a-thalasemii Cofflin-Lowryho syndrom [5] NÁDOROVÉ BUJENÍ Wilmsův renální tumor Schimkeho imunoskeletální dysplázie (Schimke immuno-osseous dysplasia, SIOD) - autosomálně recesivní komplexní syndrom charakteristický dysplázií páteře a konců dlouhých kostí, růstovou retardací, poruchy ledvin a imunity - SIOD je způsobena mutací genu SMARCAL1 (SW1/SNF2, aktin-dependentní regulátor chromatinu), který kóduje protein regulující transkripční aktivitu prostřednictvím remodelování chromatinu Schimkeho immunoskeletälnf dyspläzie SMARCAL1 From Wikipedia, the free encyclopedia SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a-like 1, also known as SMARCAL1, is a human gene [1] The protein encoded by this gene is a member of the SWI/SNF family of proteins. Members of this family have helicase and ATPase activities and are thought to regulate transcription of certain genes by altering the chromatin structure around those genes. The encoded protein shows sequence similarity to the E. coli RNA polyrnerase-binding protein HepA. Mutations in this gene are a cause ofSchimke irnmunoosseous dysplasia (SIOD), an autosomal recessive disorder with the diagnostic features of spondyloepiphyseal dysplasia, renal dysfunction, and T-cell immunodeficiency.'11 SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a-like 1 Fig. la, b Clinical photographs, a Case 1. Note the peculiar face with broad depressed nasal bridge, bulbous tip of nose and weak fine hair. The patient has a short trunk and neck, long extremities and large hands and feet, b Case 2. Note the wide nose with a bulbous tip, low-set large ears and fine weak hair. The patient has a barrel chest, short neck and relatively long extremities with large hands and feet Schimke immuno-osseous dysplasia (SIOD). SIOD is characterised by growth retardation, renal failure, spondyloepiphyseal dysplasia, specific phenotype and defective cellular immunity. These two children demonstrated a bone dysplasia with characteristic radiographic appearances. We postulate that SIOD should be considered in all cases of growth failure with an unclassifiabk bone dysplasia. Repeated urine tests for proteinuria could be helpful in reaching the correct diagnosis. Rubinstein-Taybi syndrom (RSTS): autosomální dominance - způsoben haploinsufficiencí (mutace v heterozygotním stavu) funkce genu - CREB-vazebného proteinu (regulátor fetálního růstu a vývoje), haploinsuffience vede k poklesu aktivity histon-acetyltransferáz (HAT) - u myši tento defekt může být revertován aplikací inhibitorů histon-deacetyláz (HDAC) DtOQOO ô 6 KEY □ ÓÔ □ ODO Affected Male Affected Female Wild Type Male Wild Type Female INTRACELULARNI SIGNALIZACE V MOZKU CREB = transkripční faktor cAMP-response binding protein, souvisí s HAT aktivitou, heterozygotní mutace vede k mentální retardaci: RUBINSTEIN-TAYBI syndrom (a, b) Face in RSTS. Note classical features in molecularly proven patient, (c) Talon cusps in RSTS. The presence of talon cusps is a strong indicator that the diagnosis RSTS in a patient with only partial features of RSTS is right. Facioscapulohumerální dystrofie (FSHD) -autosomálně dominantní svalová dystrofie obličeje, ramen a paží lokus FSHD'\e v subtelomerické oblasti chromosomu 4 poblíž repetice s polymorfními 3,3kb GC bohatými repeticemi Figuře 2. "Winging of the scapula" caused by weakness oi the shoulder muscles kontrakce těchto repeticí způsobuje stav vedoucí ke zvýšené transkripci přilehlých genů změna chromatinového stavu subtelomerické oblasti chromosomu 4 může vést ke změně exprese genů i syndromu choroby f Affected I parent I o o O U naff ected parent 10 10 Unaffected Unaffected Affected Affected Figure 4. Diagram of autosomal dominant inheritance. Each child has a 50% chance of inheriting FSHD from an affected parent. EPIGENETIKA A LIDSKÉ CHOROBY [1] PORUCHY IMPRINTINGU Beckwith-Wiedemannův syndrom Russell-Silverův syndrom Angelmanův syndrom Prader-Williův syndrom Pseudohypoparatyreóza [2] PORUCHY METYLACE DNA Imunodeficience ICF syndrom Metyléntetrahydrofolát reduktáza Rettův syndrom [3] PORUCHY STRUKTURY CHROMATINU Schimkeho imunoskeletální dysplázie Rubinstein-Taybiho syndrom Facioscapulohumerální svalová dystrofie [4] X-VÁZANÉ EPIGENETICKÉ PORUCHY Martin-Bellův syndrom Mentální retardace vázaná na a-thalasemii Cofflin-Lowryho syndrom [5] NÁDOROVÉ BUJENÍ Wilmsův renální tumor 5'netranslatovaná oblast FMRa FMRb 3'-netranslato Yaná oblast j........... -W*—rr-TF-F PF-P-P-T~T" J_ÍLU_li_LU_í_í_LL 5 kb □ cytosin ■ guanin 5-metyl-cytosin inaktivovaný promotor startovací repetice CGG ŕkodon promotor ' r ínlron 1 normál premutace abnormální mutace mety lace DNA [loss-of-function] 0,5 kb c> normální X má 6-60 tripletů CGG v 5UTR genu FMR1 : (CGG)10AGG(CGG)9AGG(CGG)9 š> muži-přenašeči nesou premutaci mezi 60 and 200 kopiemi š> M-B pacienti mají přes 200 kopií repetice 74,30 79 >7CO 80,30 «4 1U7 □ O no|mální □ Q přenašeč (premutace) řragilní X (M-B syndrom) 90, 30 102,30 140,30 102,30 94,30 107,30 30 >700 30 >70U >700 dominantní, X-vázaný vážná mentální retardace neúplná penetrance variabilní expresivita ^vážnější a častější u mužů Ch-E< □ I p re mutace u muže ŮÓÚÚÚÓ óôáôó© a-thalassemia X-vézaná mentální retardace (ATRX) - muži mají thalasemii (porucha syntézy hemoglobinu), mentální retardaci, mikrocefalii, neschopnost chůze aj., ženy zpravidla asymptomatické - gen ATRX(Xq13) kóduje chromatin-remodelující protein, jehož mutace způsobují blok expresi globinu a abnormální metylaci řady sekvencí DNA - nestandardní (vysoká či nízká) hladina genového produktu ATRX způsobuje stejné neurodevelopmentální defekty a-thalassemia X-vázaná mentální retardace (ATRX) X-linked alpha thalassemia: Introduction Symptoms Diagnosis Misdiagnosis Online Books Treatments Community Statistics TREATMENTS & RESEARCH Diseases » X linked alpha thalassemia mental retardation syndrome (ATR-X)»Introduction X-linked alpha thalassemia mental retardation syndrome (ATR-X) Next treatment ~. video news 1 What is Depression? The Stress of Cancer: When to Contents: X-linked alpha thalassemia mental retardation syndrome (ATR-X) 1. Introduction: X linked alpha thalassemia mental retardation syndrome (ATR-X) 2 Full Text Boohs Online 3. Svnurtonis 4. Misdiagnosis 5. Videos 6. Treatments 7 Home Diagnostic Testiim Causes 9. Stories trom Users ADVERTISEMENT Introduction: X-linked alpha thalassemia mental retardation syndrome (ATR-X) To|>0 X-linked alpha thalassemia mental retardation syndrome (ATR-X): An x-linked condition that features mental retardation, dysmorphic features, and alpha thalassemia. More detailed information about the symptoms, causes, and treatments of X-linked alpha thalassemia mental retardation syndrome (ATR-X) is available below. Symptoms of X-linked alpha thalassemia mental retardation syndrome (ATR-X) To|>0 Major Disease Research ** Hearing Babies Learn How to Communicate with Signs ADVERTISEMENT Multiple Symptom Checker. Health Tools » Symptom checker » Medical dictionary » Videos . Ask a Doctor s- Find a Doctor ■ Find a Therapist /lisdiaqnosis center ■ Forums & Message 3oards COFFLIN - LOWRY SYNDROM psychomotorická retardace, skeletální abnormity, X-vázaná choroba, souvisí s CREB, fosforyluie histon H3 Females may show mild mental retardation. The disorder is caused by a defective gene, RSK2, which was found in 1996 on the X chromosome (Xp22.2-p22.1). The gene codes for a member of a growth factor regulated protein kinase. It is unclear how changes (mutations) in the DNA structure of the gene lead to the clinical findings. EPIGENETIKA A LIDSKÉ CHOROBY [1] PORUCHY IMPRINTINGU Beckwith-Wiedemannův syndrom Russell-Silverův syndrom Angelmanův syndrom Prader-Williův syndrom Pseudohypoparatyreóza [2] PORUCHY METYLACE DNA Imunodeficience ICF syndrom Metyléntetrahydrofolát reduktáza Rettův syndrom [3] PORUCHY STRUKTURY CHROMATINU Schimkeho imunoskeletální dysplázie Rubinstein-Taybiho syndrom Facioscapulohumerální svalová dystrofie [4] X-VÁZANÉ EPIGENETICKÉ PORUCHY Martin-Bellův syndrom Mentální retardace vázaná na a-thalasemii Cofflin-Lowryho syndrom [5] NÁDOROVÉ BUJENÍ Wilmsův renální tumor Tissue-specific DNA methylation and epigenetic heterogeneity among individuals. A subset of the DNA methylation patterns within a cell are characteristic to that cell type. Cell type-specific and tissue-specific DNA methylation are illustrated by organ-to-organ variations in the clusters of methylated CpGs within the same individual. Despite overall consistency in tissue-specific DNA methylation patterns, variations in these patterns exist among different individuals. Methylated CpGs are indicated by a filled circle and unmethylated CpGs by an open circle. SNPs are indicated by the corresponding base. Epigenetické změny zahrnující metylace DNA vedou k nádorovému růstu prostřednictvím různých mechanizmů DNA methylation hypo genome instability hyper ££££ Ljl gene promoter silencing deamination meCpG TpG mutation uv carcinogen 9*9 increased carcinogen-induced UV-induced mutations mutations hydrolytická deaminace metylC vede k bodové mutaci ztráta metylace vede k nestabilitě genomu hypermetylace promotorů vede k dědičnému umlčování a k inaktivaci nádorových supresorů metylace CpG zesiluje vazbu chemických karcinogénu k DNA a zvyšuje rychlost UV-indukovaných mutací Jak mohou metylace DNA přispívat k inaktivaci genů kódujících nádorové supresory mutation mutation methylation biallelic & & & LOH methylation LOH metnylati ztráta heterozygotnosti (LOH) a přídatné epigenetické umlčování Vztah mezi metylací DNA a modifikací histonů v promotoru genu V normální buňce (gen je aktivní, rozhraní brání metylaci cytosinu v CpG oblasti), a nádorové buňce (rozhraní nefungují: dochází k aktivitě DNMT = DNA metyltransferázy, HDAC = histon deacetylázy, HKMT = histon metyltransferázy) Compound Structure Cancer Type Clinical Trials DNA METHYLATION INHIBITORS 5-Azacytidine 5-Aza-CR Vidaza J K OH OH IHj K i MDS; Hematologie malignancies I, II, and III; FDA-approved for MDS 5-Aza-2'-deoxycytidine 5-Aza-CdR Dacogen HO OH H MH, MDS; Hematologic malignancies I, II, and III Zebularine 1 -ß-D-ribofuranosyl-2(1 H)-pyrimidinone ( OH OH X N/A Preclinical Struktura nukleosidových analogů - terapeutických inhibitorů metylace DNA Inhibují metylaci cytosinu po inkorporaci do DNA: Vidaza (čs. objev) a Dacogen se používají k léčbě leukémie; Zebularine je v testování http://www-er mm.cbcu.cam.ac.uk Gross pathology of Wilms' tumour. A cut section of a Wilms' tumour showing remaining normal kidney, a large tumour (Tumour 1) and a smaller additional tumour (Tumour 2). Two x chromosome 11 Polymorphic — marker A A1 A2 x First hit Usually a point mutation or small deletion Paternal Maternal origin origin A1 A2 Blood from father of patient Blood from mother of patient Normal tissue from Wilms' patient Second hit Often a large-scale event x A- Deletion -►Wilms' tumour U Wilmsova tumoru je ztracena vždy alela A2 maternálního původu: tato oblast chromosomu 11 obsahuje imprintované geny (mj. i tumorový supresor WT1) Tumour tissue from Wilms' patient Loss of maternal allele of polymorphic marker A Southernova hybridizace s A1,2 polymorfnimi markery, nepřítomnost maternálního A2 v nádoru je důkazem větší delece CA O *J 0) c CD O) 0) L a ta c: E o o 3 a a. CL o L_ O O) c/> !5 CL O O (N © Germline epimutation of MLH1 in individuals with multiple cancers genetics Catherine M Suter1, David I K Martin2-3 & Robvn L Ward1,4 Epigenetic silencing can mimic genetic mutation by abolishing expression of a gene. We hypothesized that an epimutation could occur in any gene as a germline event that predisposes to disease and looked for examples in tumor suppressor genes in individuals with cancer. Here we report two individuals with soma-wide, allele-specific and mosaic hypermethylation of the DNA mismatch repair gene MLH1. Both individuals lack evidence of genetic mutation in any mismatch repair gene but have had multiple primary tumors that show mismatch repair deficiency, and both meet clinical criteria for hereditary nonpolyposis colorectal cancer. The epimutation was also present in spermatozoa of one of the individuals, indicating a germline defect and the potential for transmission to offspring. Germline epimutation provides a mechanism for phenocopying of genetic disease. The mosaicism and nonmendelian inheritance that are characteristic of epigenetic states could produce patterns of disease risk that resemble those of polygenic or complex traits. Epigenetic silencing is a stable but reversible alteration of gene function mediated by histone modification, cytosine methylation, the binding of nuclear proteins to chromatin and interactions among these1,2. It does not require, or generally involve, changes in DNA sequence. Errors in the elaborate apparatus of epigenetic silencing possessed by higher can predispose to cancer9. Tumor suppressors are also commonly methylated (and inactivated) in the course of neoplastic progression10, but the causal relationship between hypermethylation and tumorigene-sis has not been established. We hypothesized that some individuals are predisposed to develop cancer because they carry germline epimutations of tumor suppressor genes. We selected 94 individuals for this study: 18 with hyperplastic polyposis111 with personal histories of colorectal cancer and 65 with a family history of colorectal cancer but without deleterious germline changes in MSH2, MLH1 or APC12. We screened a subset of 44 individuals for promoter methylation of MLH1, CDKN2A, TMEFF2, HICU RASSF1, BRCA1, APC (promoters 1A and IB), BLM and MGMT. We subjected bisulfite-modified DNA from peripheral blood to e ithe r co mbined b isul fite- rest rict ion a na lysis (C OBEA)13 or met hy-lation-specific PCR (MSP)14. We identified one individual (TT) with methylation of the MLH1 (mutL homolog 1) promoter (Fig. 1). We Region A -700 -5CCI Reci ion C -i—*-1—L -300 b -100 M + TT VT Region A - u dvou pacientů s dědičným kolorektálním nádorem zjištěna somatická i germinální hypermetylace reparačního genu MLH1 VOLUME 38 | NUMBER 10 | OCTOBER 2006 NATURE GENETICS _ nature . _genetics Heritable germline epimutation of MSH2 in a family with hereditary nonpolyposis colorectal cancer Tsun Leung Chan1,2, Siu Tsan Yuen1,2,3, Chi Kwan Kong4, Yee Wai Chan1,2, Annie SY Chan1, Wai Fu Ng5, Wai Yin Tsui1, Michelle WS Lo1, Wing Yip Tarn1, Vivian SW Li1 & Suet Yi Leung1 Epimutations in the germline, such as methylation of the MLH1 gene, may contribute to hereditary cancer syndrome in human, but their transmission to offspring has never been documented. Here we report a family with inheritance, in three successive generations, of germline allele-specific and mosaic hypermethylation of the MSH2 gene, without evidence of DNA mismatch repair gene mutation. Three siblings carrying the germline methylation developed early-onset colorectal or endometrial cancers, all with microsatellite instability and MSH2 protein loss. Clonal bisulfite sequencing and pyrosequencing showed different methylation levels in different somatic tissues, with the highest level recorded in rectal mucosa and colon cancer tissue, and the lowest in blood leukocytes. This mosaic state of germline methylation with different tissue distribution could act as the first hit and provide a mechanism for genetic disease inheritance that may deviate from the mendelian pattern and be overlooked in conventional leukocyte-based genetic diagnosis strategy. - somatická i germinální hypermetylace reparačního genu MSH2 ve třech generacích pacientů s kolorektálními tumory Neurobiologie OPEN 3 ACCESS Freely available online plos one Promoter-Wide Hypermethylation of the Ribosomal RNA Gene Promoter in the Suicide Brain Patrick O. McGowan1,2,3, Aya Sasaki1,2,3, Tony C. T. Huang3,4, Alexander Unterberger3,4, Matthew Suderman3'5, Carl Ernst1 6, Michael J. Meaney1 2 3, Gustavo Turecki1 6k, Moshe Szyf3,4* 1 Department of Psychiatry, Douglas Mental Health University Institute, Montreal, Quebec, Canada, 2 Department of Neurology and Neurosurgery, McGill Program for the Study of Behaviour, Genes and Environment, McGill University, Montreal, Quebec, Canada, 3 Sackler Program for Epigenetics & Psychobiology, McGill University, Montreal, Quebec, Canada, 4Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada, 5 McGill Centre for Bioinformatics, McGill University, Montreal, Quebec, Canada, 6McGill Group for Suicide Studies, Douglas Mental Health University Institute, Montreal, Quebec, Canada Abstract Background: Alterations in gene expression in the suicide brain have been reported and for several genes DNA methylation as an epigenetic regulator is thought to play a role. rRNA genes, that encode ribosomal RNA, are the backbone of the protein synthesis machinery and levels of rRNA gene promoter methylation determine rRNA transcription. Methodoiogy/Prindpai Findings: We test here by sodium bisulfite mapping of the rRNA promoter and quantitative realtime PGR of rRNA expression the hypothesis that epigenetic differences in critical loci in the brain are involved in the pathophysiology of suicide. Suicide subjects in this study were selected for a history of early childhood neglect/abuse, which is associated with decreased hippocampal volume and cognitive impairments. rRNA was significantly hypermethylated throughout the promoter and 5' regulatory region in the brain of suicide subjects, consistent with reduced rRNA expression in the hippocampus. This difference in rRNA methylation was not evident in the cerebellum and occurred in the absence of genome-wide changes in methylation, as assessed by nearest neighbor. Conclusions/Significance: This is the first study to show aberrant regulation of the protein synthesis machinery in the suicide brain. The data implicate the epigenetic modulation of rRNA in the pathophysiology of suicide. Citation: McGowan PO, Sasaki A, Huang TCT, Unterberger A, Suderman M, et al. (2008J Promoter-Wide Hypermethylation of the Ribosomal RNA Gene Promoter in the Suicide Brain. PLoS ONE 3(5): e2085. doi:10.1371/joumal.pone.0u02035 1 (junKfos^ Promoter CdkS region gene Nature Reviews I Neuroscience Aktivace genové exprese kokainem Proposed chromatin remodelling events at a cocaine-activated gene, a | Repressed state of chromatin, where a site-specific repressor (Rep) recruits a histonedeacetylase (HDAC) complex, which removes acetyl groups (A) from histone amino-terminal tails. Gene inactivation may also involve other modifications, such as methylation (M) of histone tails, b | Active state of chromatin around a cocaine-activated gene (for example, cyclin-dependent kinase 5 {CdkS)), where a cocaine-induced transcriptionalactivator (for example, an activator protein 1 dimer composed of AFOSB-JUND) recruits a histone acetyltransferase (HAT) and a chromatin remodelling complex (mating switching and sucrose non-fermenting complex, SWI/SNF), which induce acetylation (and perhaps demethylation and other modifications) of histone tails and repositioning of nucleosomes. These actions facilitate the binding of general transcription factors and the basal transcriptional apparatus (for example, transcription factor IID (TFIID) and RNA polymerase II (PollI)) to the promoter. Search Current Issue Archive Publish Ahead of Print DNA hypermethylation of the alpha synuclein promoter in patients with alcoholism. MOLECULAR NEUROSCIENCE Neuroreport. 16(2): 167-170, Februarys, 2005. Bonsch, Dorninikus; Lenz, Bernd; Kornhuber, Johannes; Bieich, Stefan CA Abstract: The aim of this study was to investigate whether the DNA methylation pattern within the alpha synuclein promoter region is altered in intoxicated and early abstinence patients with alcoholism undergoing alcohol withdrawal. We observed a significant increase of the alpha synuclein promoter DNA methylation in patients with alcoholism which was significantly associated with their elevated homocysteine levels. No significant differences of the promoter DNA methylation within a control gene (presenilin-1) in alcoholics and controls were found. The present results hint to a gene specific DNA promoter hypermethylation within the alpha synuclein gene. Since hypermethylation of DNA is an important epigenetic factor in the down regulation of gene expression and since alpha synuclein has been linked to craving these findings may explain the reduced value of craving under alcohol drinking conditions. ACUTE IN VIVO EFFECT OF ETHANOL (BINGE DRINKING) ON HISTONE H3 MODIFICATIONS IN RAT TISSUES JEE-SOO KIM1 and SH1VENDRA D, SHUKLA* Department of Medic ill Pharmacology and Physiology, School of Medicine, University of Missouri—Columbia, Columbia, MO 65212, USA ALCOHOL AN D ALCOHOLISM Abstract — Aims: To investigate the effect of acute em vivo administration of ethanol on acetyl at ion or methylation of hi stone H 3 at lysine9 in different tissues in rat. Methods: Ethanol was injected into the stomach of Sprague—Dawley rats (K-week s-old) using biunt tipped needle. The rats were divided into three groups based on ethanol exposure times (1, 3, and 12 h). Each group was compared with water-injected control group. The tissues from 14 different organs were removed. We essentially used similar type of protocol, tissue homogenization method, and sucrose density gradient centri fug ation for isolation of nuclei with only minor modifications for some organs. Histone was isolated from the nuclei using acid extraction method. Acetyl ation of hi stone H3 at lysine9 (Ac-H3-1ys9) and methylation of histone H3 atlysine9 (Me-H3-lys9) were analysed by western blotting. Results: Effect of ethanol on Ac-H3-lys9 was investigated in 11 out of 14 rat tissues. In liver, we observed an increase in Ac-H3-lys9 with maximal increase of—6-fold after 12 h exposure. Lung also showed —3-fold increase. In spleen, ethanol-induced Ac-H3-lys9 in all three ethanol-treated groups with similar increase (1.5- to 1.6-fold). Testes showed significant increase (3-fold increase) of Ac-H3-lys9 only at 1 h ethanol exposure. Ethanol had no affect on Ac-H3-lys9 in other tissues: kidney, brain, heart, stomach, colorectum, pancreas, and vessels. Ethanol had little effect on Me-H3-lys9 in all rat tissues examined. Conclusions; After iit vivo administration of ethanol, analogous to binge drinking condition, the acetyl ation s of H3-lys9 in rat tissues are not universal but tissue-specific events with different patterns of responses. Ac-H3-Lys9 in liver, lung, and spleen were significantly affected and it was demonstrated that ethanol causes this epigenetic alteration in rat tissues selectively. Transgenerational effects of fetal and neonatal exposure to nicotine Journal Publisher ISSN Issue Category DOI Pages Subject Collection SpringerLink Date Endocrine Humana Press Inc. 0969-711X (Print) 1559-0100 (Online) Volume 31, Number 3 / June, 2007 Original Paper 10.1007/S12020-007-0043-6 254-259 Medicine Saturday, August 11, 2007 ^£ PDF (202.5 KB) ^ HTML I Alison C. Holloway1 , Donald Q. Cuu1, Katherine M. Morrison2, Hertzel C. Gerstein3 and Mark A. Tarnopolsky2, 3 (1) Reproductive Biology Division, Department of Obstetrics & Gynecology, McMaster University, RM HSC-3N52, 1200 Main Street West, Hamilton, ON, Canada, LBN 3Z5 I (2) Department of Pediatrics, McMaster University, Hamilton, ON, Canada, LBN 3Z5 I (3) Department of Medicine, McMaster University, Hamilton, ON, Canada, LBN 3Z5 Received: 27 June 2007 Revised: 19 July 2007 Accepted: 20 July 2007 Published online: 11 August 2007 I Abstract A wide variety of in utero insults are associated with an increased incidence of metabolic disorders in the offspring and in I subsequent generations. We have shown that fetal and neonatal exposure to nicotine results in endocrine and metabolic changes in I the offspring that are consistent with those observed in type 2 diabetes, This study examines whether fetal and neonatal exposure I to nicotine has transgenerational effects in the F2 offspring. Female Wistar rats were given either saline or nicotine (1 mg/kg/d) I during pregnancy and lactation to create saline- and nicotine-exposed female Fl progeny. These Fl females were then bred to I produce F2 offspring. We examined glucose homeostasis, serum lipids and fat pad weights, mitochondrial enzyme activity in skeletal I muscle and blood pressure in these F2 offspring between 13 and 15 weeks of age. Offspring of nicotine- versus saline-exposed I mothers had elevated fasting serum insulin concentrations and an enhanced total insulin response to the glucose challenge. This I apparent insulin resistance was unrelated to changes in skeletal muscle mitochondrial volume or activity. The offspring of I nicotine-exposed mothers also had elevated blood pressure. These data demonstrate that adverse effects of fetal and neonatal I exposure to nicotine can influence aspects of metabolic risk in subsequent generations, Neuron Neuron, Vol 53, 857-869,15 March 2007 Covalent Modification of DNA Regulates Memory Formation Courtney A. Miller^ and J. David Sweats ,* Department of Neurobiology and the Evelyn F. McKnight Brain InstitutejUniversity of Alabama at Birmingham, Birmingham, AL 35294, USA Summary DNA rnethylation is a covalent chemical modification of DNA catalyzed by DNA methyltransferases (DNMTs). DNA methylation is associated with transcriptional silencing and has been studied extensively as a lifelong molecular information storage mechanism put in place during development. Here we report that DNMT gene expression is upregulated in the adult rat hippocampus following contextual fear conditioning and that DNMT inhibition blocks memory formation. In addition, fear conditioning is associated with rapid methylation and transcriptional silencing of the memory suppressor gene PP1 and cfern ethyl ation and transcriptional activation of the synaptic plasticity gene reelin, indicating both methyltransferase and demethylase activity during consolidation. DNMT inhibition prevents the PP1 methylation increase, resulting in aberrant transcription of the gene during the memory-consolidation period. These results demonstrate that DNA methylation is dynamically regulated in the adult nervous system and that this cellular mechanism is a crucial step in memory formation. «lethylate negativ« memory regulators (e.g. PP1) Transcriptional repression §1 S? ± Figure 1. Fear Conditioning Is Associated with an Upregula-tion of DNMT mRNA DNMT3A, DNMT3B, and c-fcs mRNA in area CA1 are jpregulated within30 min of fear conditioning incontext-pljs-shock animals, relative to context-onlycontrols. *p < 0.05. Errorbars represent SEM. Figure 9. Schematic Representation of the Role DNA Methylation May Be Playing in the Transcriptional Regulation of Memory Formation in the Hippocampus Note: The receptors, kinases, and transcription factors depicted in gray play established roles in hippocampal memory consolidation. However, the present study does not address the potential link between these proteins and the DNA methylation we report here to be important for memory formation. Reelin From Wikipedia, the free encyclopedia Reelin is a protein found mainly in the brain, but also in the spinal cord, blood and other body organs and tissues. Reelin is crucial for regulating the processes of neuronal migration and positioning in the developing brain. Besides this important role in the early period, reelin continues to work in the adult brain. It modulates the synaptic plasticity by enhancing LTP induction and maintenance.'1"2' It also stimulates dendrite development'3' and regulates the continuing migration of neuroblasts generated in adult neurogenesis sites like subventricular and subgranular zones. Reelin is implicated in pathogenesis of several brain diseases: significantly lowered expression of the protein have been found in schizophrenia and psychotic bipolar disorder. Total lack of reelin causes a form of lissencephaly; reelin also may play a role in Alzheimer's disease, temporal lobe epilepsy, and autism. Reelin's name comes from the abnormal reeling gait of reeler mice,'4' which were found to have a deficiency of this brain protein and were homozygous for the RELN gene, which encodes reelin synthesis. The primary phenotype associated with loss of reelin function is inverted cortex, a neuroanatomical defect in which the six cortical layers are inverted. Heterozygous mice for the reelin gene have very little obvious neuroanatomical defect but those that they have resemble the changes of the human schizophrenic brain. Maternální programování epigenetických stavů Maternal ní péče jako model „experience-dependent" chromatinové plasticity serotonin mozkový transmitter camp^ cyklický adenosin monofosfát mateřská péče o novorozence (lízání a mazlení) DNA demetyláz histon-acetyltransferá protein kináza A AC Is DOBRA MATERSKÁ PECE vysoká exprese genu kódujícího glukokortikoidní receptor -STABILNÍ PSYCHIKA DOSPĚLÉHO POTOMSTVA (Ac = acetylace histonů) NGFI-A ) mozkový transkripční faktor DNMT DNA - mety I transf eráza SPATNÁ MATERSKÁ PECE nízká exprese genu GR, STRESOVÁ PSYCHIKA DOSPĚLÉHO POTOMSTVA (CH3 = metylace DNA)