CG920 Genomics Lesson 6 Gene Expression and Chemical Genetics Jan Hejátko Functional Genomics and Proteomics of Plants, CEITEC - Central European Institute of Technology And National Centre for Bimolecular Research, Faculty of Science, Masaryk University, Brno hejatko@sci.muni.cz, www.ceitec.eu 2 2  Literature sources for Chapter 05:  Surpin, M. and Raikhel, N. (2004) Traffic jams affect plant development and signal transduction. Nature Reviews/Molecular Cell Biology 5,100-109  Zouhar, J., Hicks, G.R. and Raikhel, N.V. (2004) Sorting inhibitors (Sortins): Chemical compounds to study vacuolar sorting in Arabidopsis. Proceedings of the National Academy of Sciences of the U.S.A., 101, 9497–9501  Nevo-Dinur, K., Nussbaum-Shochat, A., Ben-Yehuda, S., and Amster-Choder, O. (2011). Translation-independent localization of mRNA in E. coli. Science 331, 1081-1084.  Lecuyer, E., Yoshida, H., Parthasarathy, N., Alm, C., Babak, T., Cerovina, T., Hughes, T.R., Tomancak, P., and Krause, H.M. (2007). Global analysis of mRNA localization reveals a prominent role in organizing cellular architecture and function. Cell 131, 174-187.  Schonberger, J., Hammes, U.Z., and Dresselhaus, T. (2012). In vivo visualization of RNA in plants cells using the lambdaN(22) system and a GATEWAY-compatible vector series for candidate RNAs. The Plant journal : for cell and molecular biology 71, 173-181. Literature 3 3  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene  Preparation of translational fusion of the coding region of the analysed gene with reporter gene  Use of the data available in public databases  Tissue- and cell-specific gene expression analysis  Quantitative analysis of gene expression  DNA and protein chips  Next generation transcriptional profiling  Regulation of gene expression in the identification of gene function by gain-of-function approaches  T-DNA activation mutagenesis  Ectopic expression and regulated gene expression systems  Chemical Genetics Outline 4 4  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene Outline 5  Identification and cloning of the promoter region of the gene  Preparation of recombinant DNA carrying the promoter and the reporter gene (uidA, GFP) TATA box Iniciation of transcription promoter 5’ UTR ATG…ORF of reporter gene Transcriptional Fusion 5 6  Identification and cloning of the promoter region of the gene  Preparation of recombinant DNA carrying the promoter and the reporter gene (uidA, GFP)  Preparation of transgenic organisms carrying this recombinant DNA and their histological analysis Transcriptional Fusion 6 7 GUS Reporter in Mouse Embryos 7 8 8  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene  Preparation of translational fusion of the coding region of the analysed gene with reporter gene Outline 9  Identification and cloning of the promoter and coding region of the analyzed gene  Preparation of a recombinant DNA carrying the promoter and the coding sequence of the studied gene in a fusion with the reporter gene (uidA, GFP) TATA box promoter 5’ UTR ATG…ORF of analysed gene…..….ATG…ORF of reporter gene….….....STOP Translational Fusion 9 10  Preparation of transgenic organisms carrying the recombinant DNA and their histological analysis  Compared to transcriptional fusion, translation fusion allows analysis of intercellular localization of gene product (protein) or its dynamics Histone 2A-GFP in Drosophila embryo by PAMPIN1-GFP in Arabidopsis Translational Fusion 10 11 Translational Fusion 11 12 12  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene  Preparation of translational fusion of the coding region of the analysed gene with reporter gene  Use of the data available in public databases Outline 13 Databases □ Analysis of expression using Genevestigator (AHP1 and AHP2, Arabidopsis, Affymetrix ATH 22K Array) 13 14 Databases □ Analysis of expression using Genevestigator (AHP1 and AHP2, Arabidopsis, Affymetrix ATH 22K Array) 14 15 Databases □ Analysis of expression using ePlant 15 16 Databases □ Analysis of expression using ePlant 16 17 □ Analysis of expression using Genevestigator (AHP1 and AHP2, Arabidopsis, Affymetrix ATH 22K Array) Databases 17 18 18  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene  Preparation of translational fusion of the coding region of the analysed gene with reporter gene  Use of the data available in public databases  Tissue- and cell-specific gene expression analysis Outline 19 Fluorescence-Activated Cell Sorting (FACS) □ High-Resolution Expression Map in Arabidopsis Root Expression Maps - RNA Brady et al., Science, 2007 Microarray expression profiles of 19 fluorescently sorted GFP-marked lines were analyzed (3–9, 23, 24). The colors associated with each marker line reflect the developmental stage and cell types sampled. Thirteen transverse sections were sampled along the root's longitudinal axis (red lines) (10). CC, companion cells. 19 20 □ High-Resolution Expression Map in Arabidopsis Root Expression Maps - RNA Brady et al., Science, 2007 (A) The majority of enriched GO terms (hierarchically clustered) are associated with individual cell types (blue bar). A smaller number are present across multiple cell types (green bar). (fig. S2) (B) GO category enrichment for hair cells confirms a previous report (15). Enriched cis-elements and an enriched TF family were also identified. (C) From the top 50% of varying probe sets, 51 dominant radial patterns were identified. Pattern expression values were mean-normalized (rows) and log2 transformed to yield relative expression indices for each marker line (columns). Marker line order is the same for all figures; see table S1 for marker line abbreviations. (D) Pattern expression peaks were found across one to five cell types. (E to G) Patterns where expression is enriched in single and multiple cell types support transcriptional regulation of auxin flux and synthesis. In all heat maps with probe sets, expression values were mean-normalized and log2 transformed. Expression is false-colored in representations of a root transverse section, a cut-away of a root tip, and in a lateral root primordium. (E) Auxin biosynthetic genes (CYP79B2, CYP79B3, SUPERROOT1, and SUPERROOT2) are transcriptionally enriched in the QC, lateral root primordia, pericycle, and phloem-pole pericycle (P = 1.99E–11, pattern 5). All AGI identifiers and TAIR descriptions are found in table S14. (F) Auxin amido-synthases GH3.6 and GH3.17 that play a role in auxin homeostasis show enriched expression in the columella, just below the predicted auxin biosynthetic center of the QC (P = 8.82E–4, pattern 13). (G) The expression of the auxin transporter, PINFORMED2, and auxin transport regulators (PINOID, WAG1) are enriched in the columella, hair cells, and cortex (P = 1.03E–4, pattern 31). 20 21 □ High-Resolution Expression Map in Drosophilla Expression Maps - RNA Nikos Karaiskos et al. Science 2017;science.aan3235 Deconstructing and reconstructing the embryo by single-cell transcriptomics combined with spatial mapping. (A) Single-cell sequencing of the Drosophila embryo: ~1000 handpicked stage 6 fly embryos are dissociated per Drop-seq replicate, cells are fixed and counted, single cells are combined with barcoded capture beads, and libraries are prepared and sequenced. Finally, single-cell transcriptomes are deconvolved, resulting in a digital gene expression matrix for further analysis. (B) Mapping cells back to the embryo: Single-cell transcriptomes are correlated with high-resolution gene expression patterns across 84 marker genes, cells are mapped to positions within a virtual embryo, and expression patterns are computed by combining the mapping probabilities with the expression levels (virtual in situ hybridization). 21 22 Expression Maps - Proteins Ponten et al., J Int Med, 2011 □ Human Protein Atlas Schematic flowchart of the Human Protein Atlas. For each gene, a signature sequence (PrEST) is defined from the human genome sequence, and following RT-PCR, cloning and production of recombinant protein fragments, subsequent immunization and affinity purification of antisera results inmunospecific antibodies. The produced antibodies are tested and validated in various immunoassays. Approved antibodies are used for protein profiling in cells (immunofluorescence) and tissues (immunohistochemistry) to generate the images and protein expression data that are presented in the Human Protein Atlas (Ponten et al., J Int Med, 2011). 22 23 □ Human Protein Atlas (http://www.proteinatlas.org/) Expression Maps - Proteins 23 24 □ Human Protein Atlas (http://www.proteinatlas.org/) Expression Maps - Proteins 24 25 25  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene  Preparation of translational fusion of the coding region of the analysed gene with reporter gene  Use of the data available in public databases  Tissue- and cell-specific gene expression analysis  Quantitative analysis of gene expression  DNA and protein chips Outline 26 26  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene  Preparation of translational fusion of the coding region of the analysed gene with reporter gene  Use of the data available in public databases  Tissue- and cell-specific gene expression analysis  Quantitative analysis of gene expression  DNA and protein chips Outline 27  Method, which provides quick comparison of a large number of genes/proteins between the test sample and control  Oligo DNA chips are used the most  There are commercialy available kits for the whole genome  company Operon (Qiagen), 29.110 of 70-mer oligonucleotides representing 26.173 genes coding proteins, 28.964 transcripts and 87 microRNA genes of Arabidopsis thaliana  Possibility of use for the preparation of photolithography chips – facilitation of oligonucletide synthesis e.g. for the whole human genome (about 3,1 x 109 bp) jit is possible to prepare 25-mers in only 100 steps, by this technique Affymetrix ATH1 Arabidopsis genome array  Chips not only for the analysis of gene expression, but also for e.g. Genotyping (SNPs, sequencing with chips, …) DNA Chips 27 28  For the correct interpretation of the results, good knowledge of advanced statistical methods is required  Control of accuracy of the measurement (repeated measurements on several chips with the same sample, comparing the same samples analysed on different chips with each other)  It is necessary to include a sufficient number of controls and repeats  Control of reproducibility of measurements (repeated measurements with different samples isolated under the same conditions on the same chip – comparing with each other) Che et al., 2002  Identification of reliable measurement treshold nespolehlivé spolehlivé  Finally comparing the experiment with the control or comparing different conditions with each other > the result  Currently there‘s been a great number of results of various experiments in publicly accessible databases DNA Chips 28 29  Protein chips  Chips with high density containing 104 proteins  Analysis of protein-protein interactions, kinase substrates and interactions with small molecules  Possibility of using antibodies – more stable than proteins Protein Chips 29 30  Identification of proteins interacting with integrin αIIbβ3 cytoplasmic domain of platelets  Expression of cytoplasmic part as a fusion peptide biotin-KVGFFKR  Analysis of binding to the protein chip containing 37.000 clones of E. coli expressing human recombinant proteins  Confirmation of interaction by pulldown analysis of peptides and by coprecipitation of whole proteins as well (e.g. chloride channel Icln)  Other use: e.g. in the identification of kinase substrates, when substrates are bound to the chip and exposed to kinases in the presense of radiolabeled ATP (786 purified proteins of barely, of which 21 were identified as CK2α kinase substrates; Kramer et al., 2004) Lueking et al., 2005 Protein Chips 30 31 31  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene  Preparation of translational fusion of the coding region of the analysed gene with reporter gene  Use of the data available in public databases  Tissue- and cell-specific gene expression analysis  Quantitative analysis of gene expression  DNA and protein chips  Next generation transcriptional profiling Outline 32 WT hormonal mutant Next Gen Transcriptional Profiling □ Transcriptional profiling via RNA sequencing mRNA Sequencing by Illumina and number of transcripts determination mRNA cDNA cDNA 32 33 Results of –omics Studies vs Biologically Relevant Conclusions □ Transcriptional profiling yielded more then 7K differentially regulated genes… gene locus sample_1 sample_2 status value_1 value_2 log2(fold_change) test_stat p_value q_value significant AT1G07795 1:2414285-2414967 WT MT OK 0 1,1804 1.79769e+308 1.79769e+3 08 6.88885e-05 0,00039180 1 yes HRS1 1:4556891-4558708 WT MT OK 0 0,696583 1.79769e+308 1.79769e+3 08 6.61994e-06 4.67708e- 05 yes ATMLO14 1:9227472-9232296 WT MT OK 0 0,514609 1.79769e+308 1.79769e+3 08 9.74219e-05 0,00053505 5 yes NRT1.6 1:9400663-9403789 WT MT OK 0 0,877865 1.79769e+308 1.79769e+3 08 3.2692e-08 3.50131e- 07 yes AT1G27570 1:9575425-9582376 WT MT OK 0 2,0829 1.79769e+308 1.79769e+3 08 9.76039e-06 6.647e-05 yes AT1G60095 1:22159735-22162419 WT MT OK 0 0,688588 1.79769e+308 1.79769e+3 08 9.95901e-08 9.84992e- 07 yes AT1G03020 1:698206-698515 WT MT OK 0 1,78859 1.79769e+308 1.79769e+3 08 0,00913915 0,0277958 yes AT1G13609 1:4662720-4663471 WT MT OK 0 3,55814 1.79769e+308 1.79769e+3 08 0,00021683 0,00108079 yes AT1G21550 1:7553100-7553876 WT MT OK 0 0,562868 1.79769e+308 1.79769e+3 08 0,00115582 0,00471497 yes AT1G22120 1:7806308-7809632 WT MT OK 0 0,617354 1.79769e+308 1.79769e+3 08 2.48392e-06 1.91089e- 05 yes AT1G31370 1:11238297-11239363 WT MT OK 0 1,46254 1.79769e+308 1.79769e+3 08 4.83523e-05 0,00028514 3 yes APUM10 1:13253397-13255570 WT MT OK 0 0,581031 1.79769e+308 1.79769e+3 08 7.87855e-06 5.46603e- 05 yes AT1G48700 1:18010728-18012871 WT MT OK 0 0,556525 1.79769e+308 1.79769e+3 08 6.53917e-05 0,00037473 6 yes AT1G59077 1:21746209-21833195 WT MT OK 0 138,886 1.79769e+308 1.79769e+3 08 0,00122789 0,00496816 yes AT1G60050 1:22121549-22123702 WT MT OK 0 0,370087 1.79769e+308 1.79769e+3 08 0,00117953 0,0048001 yes Ddii et al., unpublished AT4G15242 4:8705786-8706997 WT MT OK 0,00930712 17,9056 10,9098 -4,405231.05673e-05 7.13983e-05 yes AT5G33251 5:12499071-12500433 WT MT OK 0,0498375 52,2837 10,0349 -9,8119 0 0 yes AT4G12520 4:7421055-7421738 WT MT OK 0,0195111 15,8516 9,66612 -3,900439.60217e-05 0,000528904 yes AT1G60020 1:22100651-22105276 WT MT OK 0,0118377 7,18823 9,24611 -7,503826.19504e-14 1.4988e-12 yes AT5G15360 5:4987235-4989182 WT MT OK 0,0988273 56,4834 9,1587 -10,4392 0 0 yes Excample of an output of transcriptional profiling study using Illumina sequencing performed in our lab. Shown is just a tiny fragment of the complete list, copmprising about 7K genes revealing differential expression in the studied mutant. 33 34 34  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene  Preparation of translational fusion of the coding region of the analysed gene with reporter gene  Use of the data available in public databases  Tissue- and cell-specific gene expression analysis  Quantitative analysis of gene expression  DNA and protein chips  Next generation transcriptional profiling  Regulation of gene expression in the identification of gene function by gain-of-function approaches  T-DNA activation mutagenesis Outline 35  Methods for identification of gene function using gain-of-function approaches  T-DNA activation mutagenesis  Method enabling isolation of dominant mutants by random insertion of constitutive promoter, resulting in overexpression of the gene and therefore in corresponding phenotypic changes  First step: preparation of mutant library prepared by tansformation of a strong constitutive promoter or enhancer  Next step: search of interesting phenotypes  Identification of the affected gene, e.g. by plasmid-rescue Gain-of-Function Approaches 35 36 TF TF TF 40S 60S TF TF TF TF 40S 60S 40S 60S 40S 60S 40S 60S TF TF TF Activation Mutagenesis 36 37 Isolation of CKI1 Gene - Isolation of the gene using activation mutagenesis - Mutant phenotype is a phenocopy of exogenous application of cytokinins (CKI1, CYTOKININ INDEPENDENT 1) *- Tatsuo Kakimoto, Science 274 (1996), 982-985 * * no hormones t-zeatin K1 K2plasmid rescue 35S::CK 1 cDNA 37 38 38  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene  Preparation of translational fusion of the coding region of the analysed gene with reporter gene  Use of the data available in public databases  Tissue- and cell-specific gene expression analysis  Quantitative analysis of gene expression  DNA and protein chips  Next generation transcriptional profiling  Regulation of gene expression in the identification of gene function by gain-of-function approaches  T-DNA activation mutagenesis  Ectopic expression and regulated gene expression systems Outline 39 35S LhG4 pOP TATA CKI1 activator reporter activator x reporter x Regulated Expression Systems 39 40 35S LhGR pOP TATA CKI1 activator reporter activator x reporter DEX DEX +DEX DEX DEX DEX x Regulated Expression Systems 40 41 35S LhGR pOP TATA CKI1 activator reporter activator x reporter DEX DEX +DEX DEX DEX DEX x pOP TATA GUS DEX DEX wt Col- 0 4C Regulated Expression Systems 41 42 42  UAS system http://www.plantsci.cam.ac.uk/Haseloff/  Regulatable gene expression systems  Time- or site-specific regulation of gene expression, leading to a change in phenotype and thereby identification of the natural function of the gene  pOP system Regulated Expression Systems 43 43  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene  Preparation of translational fusion of the coding region of the analysed gene with reporter gene  Use of the data available in public databases  Tissue- and cell-specific gene expression analysis  Quantitative analysis of gene expression  DNA and protein chips  Next generation transcriptional profiling  Regulation of gene expression in the identification of gene function by gain-of-function approaches  T-DNA activation mutagenesis  Ectopic expression and regulated gene expression systems  Chemical Genetics Outline 44 44  New trends  „chemical genetics“ – more than 50.000/120.417 records in PubMed database (16.10. 2008/15.11. 2018, an increase of >240 %) Chemical Genetics 45 45  New trends  „chemical genetics“ – more than 50.000/130.437 records in PubMed database (16.10. 2008/24.10. 2019, an increase of >260 %) Chemical Genetics  Like in the case of genetics, there are also „forward“ and „reverse“ genetics approaches  Unlike in „classical“ genetics approaches, the subject of study is not a gene, but a protein  Chemical genetics tries to identify either the target protein after a chemical treatment and after following phenotypic changes („forward“ chemical genetics) or chemicals able to interact with protein of interest („reverse“ chemical genetics)  For that purpose there are carried out searches in the libraries of various chemicals (thousands of entries, comercially available)  example: analysis of endomembrane transport in plants 46  Analysis of mechanisms of endomembrane transport by chemical genetics approaches  In plants cells there occurr very dynamic processes mediated mainly by endomembrane transport Chemical Genetics GFP targeted to the ER 46 47  Endomembrane transport is an important regulatory mechanism in signal transduction and regulation of cellular processes  Analysis of mechanisms of endomembrane transport by chemical genetics approaches  In plants cells there occurr very dynamic processes mediated mainly by endomembrane transport (see film, GFP targeting to the ER) Chemical Genetics 47 48 Richter et al., E J Cell Biol (2010) Anterograde transport Retrograde transport Trans-Golgi network Multivesicular bodies-late endosome (prevacuolar compartment) Recycling endosome Huang et al., 2010 PIN1-GFP In the figure, there is simplified scheme of vesicle trafficking pathways, regulated by GNOM and its closest relative, GNOM-LIKE1 (GNL1). Secretory and membrane proteins are synthesised at the ER (blue) and passed onto the Golgi apparatus (green) by anterograde trafficking in COPII-coated vesicles. The retrograde route from the Golgi apparatus to the ER is regulated by the ARFGEFs GNOM (GN) and GNL1, which regulate the recruitment of COPI coats to the Golgi membrane. On the secretory route, proteins are transported to the sorting station, the trans-Golgi network (TGN; lilac). From there, proteins are either transported to the vacuole (grey) via multivesicular bodies (MVB, also called prevacuolar compartment, PVC, which corresponds to the late endosome; deep blue) or trafficked to the plasma membrane (PM). Plasma membrane proteins like the auxin efflux carrier PIN1 (red), which accumulates at the basal PM at steady state, are continually internalised and trafficked to the TGN, which resembles the early endosome (EE) in plants. From the TGN, PIN1 is recycled to the plasma membrane via the recycling endosome (RE; light blue). This pathway is regulated by the ARF-GEF GNOM. 48 49  Analysis of mechanisms of endomembrane transport by chemical genetics approaches  By searching in the „library“ of chemicals there were identified those, that lead to the secretion of enzyme (carboxypeptidase Y) in yeast (S. cerevisiae) – this enzyme is normally transported to the vacuole via the endomembrane transport  Analysis of changes in secretion using dotblot and immunodetection of carboxypeptidase Y in the culture medium with monoclonal antibodies Zouhar et al., 2004 Chemical structure of sortins Detection of vacuole phenotype (tonoplast shape) of yeast by staining with a specific color (MDY-64) Immunodetection of carboxypeptidase Chemical Genetics 49 50  Analysis of mechanisms of endomembrane transport by chemical genetics approaches  Identified compounds („sortins“) were able to induce similar changes in Arabidopsis as well – transport mechanisms are conserved in yeast and in plants  For detailed identification of the molecular proces affected by one of the identified „sortins“, the analysis of its influence on a secretion of a marker protein (AtCPY) was performed – sortin 1 specifically inhibits only this secretory pathway  Identifcation of mutants with altered sensitivity to sortin 1 (hyper- or hypo-sensitive mutants) by EMS mutagenesis Zouhar et al., 2004 Shape of plant vacuoles using EGFP:-TIP Phenotype of seedlings in the presence of sortins Sortin 1 Sortin 2  By searching in the „library“ of chemicals there were identified those, that lead to the secretion of enzyme (carboxypeptidase Y) in yeast (S. cerevisiae) – this enzyme is normally transported to the vacuole via the endomembrane transport  Analysis of changes in secretion using dotblot and immunodetection of carboxypeptidase Y in the culture medium with monoclonal antibodies Chemical Genetics 50 51  Analysis of mechanisms of endomembrane transport by chemical genetics approaches – summary  GFP::d-TIP vacuole membrane (tonoplast) labelling and identification of mutations leading to altered tonoplast morphology  Chemical genetics in combination with classical genetics – identification of proteins participating in regulation of endomembrane transport  Proteomics approaches – identification and analysis of vacuole proteome 51 52 52  Methods of gene expression analysis  Qualitative analysis of gene expression  Preparation of transcriptional fusion of promoter of analysed gene with a reporter gene  Preparation of translational fusion of the coding region of the analysed gene with reporter gene  Use of the data available in public databases  Tissue- and cell-specific gene expression analysis  Quantitative analysis of gene expression  DNA and protein chips  Next generation transcriptional profiling  Regulation of gene expression in the identification of gene function by gain-of-function approaches  T-DNA activation mutagenesis  Ectopic expression and regulated gene expression systems  Chemical Genetics Summary 53 53 Discussion