March 3, 2010Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 905_02_DNA.jpg05_10_Genes_info.jpg07_37_Protein.produc.jpg08_03_control.steps.jpgSlide 14Slide 1508_13_gene.activation.jpgTranscription factors05_24_Chromatin pack.jpg05_30_histone tails.jpg08_14_chromatin.struc.jpg08_15_Reg. proteins.jpg08_18_reporter.gene.jpgSlide 23Signals can regulate activity of transcription factors08_23_cell.memory.jpg08_24_chromatin.state.jpgSlide 27Slide 28Slide 2910_14_1_Southrn.blotting.jpg10_14_2_Southrn.blotting.jpgSlide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38March 3, 2010Introduction to developmentGene expressionWhat cellular functions are needed to carry out development?What cellular functions are needed to carry out development?DivideGrowDifferentiateDieMoveAdhereSecreteSignalCell biological properties need to be coordinated in space and timeWhere is the “program” for development encoded?Where is the “program” for development encoded?In the genesWhy do different cells behave differently?Why do different cells behave differently?Have different genes?Have different histories?Experience different environments?Chance?Have different gene expression states?Why do different cells behave differently?Have different genes?Have different histories?Experience different environments?Chance?Have different gene expression states?05_02_DNA.jpg05_10_Genes_info.jpgGenesCarry out functions07_37_Protein.produc.jpgSteps in gene expression08_03_control.steps.jpgmRNA localization control(tether mRNA to localized proteins)mRNA turnover control(microRNAs)Protein turnover control(ubiquitylation and proteasome digestion)Protein localization controlRegulation of gene expression08_03_control.steps.jpgmRNA localization control(tether mRNA to localized proteins)mRNA turnover control(microRNAs)Protein turnover control(ubiquitylation and proteasome digestion)Protein localization controlRegulation of gene expressioncoding strandRegulation of transcription:Parts of a gene08_13_gene.activation.jpgRegulation of transcriptionTranscription factors05_24_Chromatin pack.jpgNucleosomes (histones) package DNA05_30_histone tails.jpgHistone modifications affect gene expressionCan affect recruitment of transcription factors to promoter08_14_chromatin.struc.jpgSome transcription factors affect histones08_15_Reg. proteins.jpgMultiple transcription factors regulate most genes08_18_reporter.gene.jpgModularity of the Drosophila even-skipped promoterCoordinated regulation of multiple genesDevelopmental functionsSignals can regulate activity of transcription factors08_23_cell.memory.jpgMaintaining gene expression states(a positive feedback loop)08_24_chromatin.state.jpgMaintaining gene expression statesThe histone code also needs to be maintained in daughter cellsMaintaining gene expression states – DNA methylationHow does one monitor which genes a particular cell expresses?10_14_1_Southrn.blotting.jpgSouthern blot10_14_2_Southrn.blotting.jpgSouthern blot – DNA on blotNorthern blot – RNA on blotNorthern blot hybridization(tests one gene at a time)In situ hybridization of developing flowers with ARF6 probeFrom Wildwater et al., Cell 123: 1337-1349 (2005)Rb-Related expression in Arabidopsis embryosby in situ hybridization08_18_reporter.gene.jpgPromoter:reporter fusion gene in a transgenic fly embryoPARF6::ARF6::GUS fusion expression in flowers and ovulesPromoter:protein:reporter fusion gene – reveals protein locationKosman et al., Science 254: 118-122 (1991)anti-Snailanti-TwistImmunolocalization of Snail and Twist proteins in Drosophila embryosUtility of looking at expression of single genes at a time:Markers of cell type, differentiationVisualization of regulatory eventsUtility of looking at expression of many genes at once:Global view of tissue identityComparing different tissues or statesGlobal view of regulatory
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