基因表达和调控

1、Basic concept of transcriptionAn example of genetic control of metabolism The products of gene expression can be RNA or proteinBasic concept of transcriptionA transcription unit：PROKARYOTES AND THEIR VIRUS调节基因调节基因操纵子操纵子Lac 阻遏物阻遏物半乳糖苷酶半乳糖苷酶半乳糖苷半乳糖苷透性酶透性酶半乳糖苷半乳糖苷乙酰基转移酶乙酰基转移酶E.Coli 诱导型诱导型Lac操纵子结构模型操纵子结

2、构模型基基因因 长长度度PI: i基因启动子基因启动子 gene i：调节基因：调节基因 P： 结构基因启动子结构基因启动子 gene Z,Y,A：结构基因：结构基因 O： 操纵单元操纵单元 Lac 操纵子基因的组成型表达：操纵子基因的组成型表达： 外源诱导物不存在时，外源诱导物不存在时， 功能基因仍表达功能基因仍表达THE CENTRAL DOGMAThe difference of gene expression between prokaryotes and eukaryotes Basic concept of transcriptionBasic concept of transcr

3、iptionBasic concept of transcriptionBasic concept of transcriptionBasic concept of transcriptionBasic concept of transcriptionBasic concept of transcriptionRNA SYNTHESISBasic concept of transcriptionBasic concept of transcriptionRNA initiation in E. coliA:T rich region Initiate unwindingRNA polymera

4、se binding siteTranscription begins Basic concept of transcriptionPROMOTEROF BACTERIABasic concept of transcriptionBasic concept of transcriptionRNA elongation in E. coliA Rho-dependent transcription terminator: result in termination only in the presence of protein rho()A Rho-independent transcripti

5、on terminator: result in termination without the involvement of protein rho()Basic concept of transcriptionBasic concept of transcriptionBasic concept of transcriptionA Rho-independent transcription terminatorBasic concept of transcriptionTranscription in Eukaryotes:Basic concept of transcriptionBas

6、ic concept of transcriptionBasic concept of transcriptionStructure of a promoter recognized by RNA polymerase IIBasic concept of transcriptionBasic concept of transcriptionInitiation of transcription by RNA polymerase IIBasic concept of transcriptionBasic concept of transcriptionBasic concept of tra

7、nscriptionRNA elongation and the addition of 5- capBasic concept of transcriptionRNA termination and the addition of 3- poly(A) tails RNA processing RNA SPLICING RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA

8、 processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processing RNA processingRNA EDITING:Genetic information is altered in the mRNA RNA processing RNA proce

9、ssingEditing of the apolipoprotein-B mRNA in the intestines of mammals RNA processingEditing of the mitochondrial cytochrome b pre-mRNA RNA processingThe two-step mechanism by which uridine monophosphate residues are inserted into pre-mRNA molecules during editing in mitochondria of trypanosomes RNA

10、 processing RNA processing RNA processing 2.RNA processing 4.Translation4.Translation5.Post-translation3.RNA stability5 levels of regulation: TRANSLATION TRANSLATION TRANSLATION TRANSLATION TRANSLATION TRANSLATION TRANSLATION TRANSLATION TRANSLATION TRANSLATION TRANSLATION TRANSLATION TRANSLATION TR

11、ANSLATION TRANSLATION TRANSLATION TRANSLATIONPROKARYOTES AND THEIR VIRUSPROKARYOTES AND THEIR VIRUSBacteriophage lambdaTwo intracellular states：Lytic growthlysogenyPROKARYOTES AND THEIR VIRUSRepression of the lambda lytic genes in lysogenic E.coli PROKARYOTES AND THEIR VIRUSThe lambda repressor dime

12、r contacts its binding sites in lambda operator region(OL and OR) PROKARYOTES AND THEIR VIRUSAutogenous regulation of phage lambda repressor synthesisPROKARYOTES AND THEIR VIRUSGenes and recognition sites invovled in the lambda lytic regulatory casadeGenes cro, N and Q encode regulatory proteins req

13、uired for lytic development PROKARYOTES AND THEIR VIRUSFunctions of the cro gene productPROKARYOTES AND THEIR VIRUSN protein functions as an antiterminator of transcriptionPROKARYOTES AND THEIR VIRUSPROKARYOTES AND THEIR VIRUSRegulatory element involved in setting the lambda genetic switch to lytic

14、or to lysogeny growthPROKARYOTES AND THEIR VIRUSThe lambda CII-CIII-PRE regulatory circuitPROKARYOTES AND THEIR VIRUSSummary of the lambda regulatory elementsPROKARYOTES AND THEIR VIRUSPROKARYOTES AND THEIR VIRUSPROKARYOTES AND THEIR VIRUSThe coordination between ribosomal protein synthesis and ribo

15、somal RNA synthesis occurs at the level of translation PROKARYOTES AND THEIR VIRUSPROKARYOTES AND THEIR VIRUSPROKARYOTES AND THEIR VIRUSFeedback inhibition or end-product inhibitioneukaryotesOrgnanization and temporally specific expression of human and globin geneseukaryotesThe stages at which eukar

16、yotic gene expression can be regulated:TranscriptionProcessingTranslationeukaryoteseukaryoteseukaryoteseukaryoteseukaryoteseukaryoteseukaryotesEnvironment factors induce transcriptional activity: temperatureeukaryoteseukaryotesBiological factors induce transcriptional activity1: steroid hormoneseukaryotesBiological factors induce transcriptional activity2: peptide hormoneeukaryotesDNA sequences involved in