Lecture 37 Transcriptional Regulation 1 Please identify the TRUE statements associated with cis factors that regulate transcription choose all that apply a Cis factors are proteins which bind regulatory DNA sequences b Promoters and repressors are both examples of cis factors c Enhancers and silencers are both examples of cis factors d Silencer elements are cis factors that bind to regions of the DNA known as repressors 2 Helix turn helix B zip zinc finger domains are all examples of DNA binding domains DBD effector domains ED 3 Effector Domains participate in gene activation or repression by a Recruiting other proteins that stabilize or inhibit the binding of the polymerase to the promoter b Interacting with polymerase itself to stabilize or inhibit the polymerase on the promoter c Interacting with mediator proteins that bridge to the polymerase d All the above e a and b only 4 In transcription factors that have a helix turn helix domain both helices interact with bases in the major groove to make stable associations with the DNA True False 5 Which of the following have helix turn helix domains a CAP b The lac repressor c The trp repressor d Homeodomain proteins e Estrogen receptor f All the above g Only a through d h Only a b and c 6 Of the transcription factors in Q5 which are examples of eukaryotic factors d and e 7 Many prokaryotic genes organized into transcription units by function those genes involved in the same pathway are regulated by one promoter region Such polygenic units are called operons 8 In the repressor inducer complex involved in the regulation of this transcriptional unit what are the identities of the repressor and the inducer a Repressor lac repressor b This protein is transcribed from what gene lac I c Inducer Allolactose d This inducer is produced from what disaccharide Lactose e When the repressor is bound by the inducer the repressor s affinity for DNA is increased decreased Lecture 37 Transcriptional Regulation 9 What effect does the presence of the following carbohydrates in the growing medium have on the regulation of transcription of the lac z lac y and lac a genes a Lactose forms the inducer allolatose which through binding the repressor and decreasing its affinity for DNA allows transcription of the lac operon b Glucose When glucose is present in the medium the CAP protein will not be bound to activate the lac operon above basal levels when lactose is present You should be ready to interpret whether these genes in the lac transcriptional unit will be activated or repressed when given specific scenarios 10 Where does the repressor bind in this transcriptional unit a Promoter b Regulator c Operator d Enhancer 11 When the estrogen receptor a cell surface protein binds estrogen it is endocytosed and then the receptor travels to the nucleus to bind DNA True False 12 The estrogen receptor affects transcription through directly binding to the polymerase at the site of transcription True False Please be prepared to state how the drug Tamoxifen works
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