Download
slide1 n.
Skip this Video
Loading SlideShow in 5 Seconds..
Each structural gene has its own promoter, and is transcribed separately. PowerPoint Presentation
Download Presentation
Each structural gene has its own promoter, and is transcribed separately.

Each structural gene has its own promoter, and is transcribed separately.

161 Views Download Presentation
Download Presentation

Each structural gene has its own promoter, and is transcribed separately.

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. 17.1 Eukaryotic Cells and Bacteria Have Many Features of Gene Regulation in Common, but They Differ in Several Important Ways • Each structural gene has its own promoter, and is transcribed separately. • DNA must unwind from the histone proteins before transcription. • Activators are more common in Eukaryotes. • Transcription and translation are separated in time and space.

  2. 17.2 Changes in Chromatin Structure Affect the Expression of Genes • DNase I hypersensitivity • DNase I hypersensitive sites: more open chromatin configuration site, upstream of the transcription start site • Histone modification • Addition of methyl groups to the histone protein tails • Addition of acetyl groups to histone proteins

  3. 17.2 Changes in Chromatin Structure Affect the Expression of Genes • Chromatin remodeling • Chromatin-remodeling complexes: bind directly to DNA sites and reposition nucleosomes • DNA methylation of cytosine bases adjacent to guanine nucleotides (CpG)–CpG islands

  4. 17.3 The Initiation of Transcription Is Regulated by Transcription Factors and Transcriptional Activator Proteins • Trancriptional activators, coactivators, and repressors

  5. 17.3 The Initiation of Transcription Is Regulated by Transcription Factors and Transcriptional Activator Proteins • Transcriptional activator protein GAL4

  6. Concept Check 1 Most transcriptional activator proteins affect transcription by interacting with . • introns • the basal transcription apparatus • DNA polymerase • nucleosomes

  7. Concept Check 1 Most transcriptional activator proteins affect transcription by interacting with . • introns • the basal transcription apparatus • DNA polymerase • nucleosomes

  8. 17.3 The Initiation of Transcription Is Regulated by Transcription Factors and Transcriptional Activator Proteins • Enhancers and insulators • Enhancer: DNA sequence stimulating transcription from a distance away from promoter • May increase transcription of many genes in vicinity • Insulator: DNA sequence that blocks or insulates the effect of enhancers

  9. 17.3 The Initiation of Transcription Is Regulated by Transcription Factors and Transcriptional Activator Proteins • Coordinated gene regulation • Response elements: common regulatory elements upstream of the start sites of a collective group of genes in response to a common environmental stimulus • Heat-shock proteins

  10. 17.4 Some Genes Are Regulated by RNA Processing and Degradation • Gene regulation through RNA splicing

  11. 17.4 Some Genes Are Regulated by RNA Processing and Degradation • The degradation of RNA • 5′-cap removal • Shortening of the poly(A) tail • Degradation of 5′ UTR, coding sequence, and 3′ UTR

  12. 17.5 RNA Interference Is an Important Mechanism of Gene Regulation • Small interfering RNAs and microRNAs • RISC: RNA-induced silencing complex

  13. 17.5 RNA Interference Is an Important Mechanism of Gene Regulation • Mechanisms of Gene regulation by RNA interference • RNA cleavage: RISC containing an siRNA, pair with mRNA molecules and cleavage to the mRNA • Inhibition of translation • Transcriptional silencing: altering chromatin structure • Silencer-independent degradation of mRNA

  14. 17.6. Some Genes Are Regulated by Processes That Affect Translation or by Modification of Proteins • Model Genetic Organism • The plant Arabidopsis thaliana