Lecture27_euk_gene_express

Lecture27_euk_gene_express - Announcements 2 more quizzes...

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1 Control of Gene Expression in Eukaryotes Lecture 27 Announcements • 2 more quizzes to smartsite this afternoon – Only 100 quiz points ‘count’ toward your score • Final – two rooms – look for announcement on Smartsite – MC questions only, about 75 questions – About 50% of exam on Unit 3 Last one-minute paper • Why do cells control gene regulation? Transcriptional activation in eukaryotes In eukaryotes, general transcription factors (regulatory proteins) must assemble on the chromosome before RNA polymerase can bind to the promoter and begin transcription. The transcription factors form a transcription initiation complex . Specialized enhancers fine-tune gene expression Enhancers are non- coding DNA, 100s of base pairs long Can be remote from the gene controlled Regulatory proteins bind to the DNA Activators are special transcription factors that bind to enhancers
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2 Transcription factors Enhancer Gene Transcription initiation complex: All parts must be present to turn gene “on” Results in protein synthesis and cell specialization (differentiation) Eukaryotic gene structure and regulation Each cell in the organism contains the same set of genes However, not all genes are actively functioning in all cells To function, a gene must be transcribed into mRNA and then translated into protein When and where each gene is transcribed is determined by its regulatory sequences ( enhancers ) In genes that contain multiple enhancers, each enhancer may be responsible for "gene expression" (transcription) in a different tissue, or at a different time This modular organization allows each gene to perform multiple functions independently Eukaryotic gene structure and regulation Transcription factors Enhancers control gene expression by interacting with sequence-specific transcription factors Neither transcription factor nor enhancer sequence can do anything on their own. The binding of the protein to DNA is necessary to activate transcription. Different TFs bind to different enhancer sequences.
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This note was uploaded on 03/08/2011 for the course BIS 2A taught by Professor Grossberg during the Fall '08 term at UC Davis.

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Lecture27_euk_gene_express - Announcements 2 more quizzes...

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