BIO 311C Chapter Notes - Chapter 18: Primase, Helicase, Tata Box
Document Summary
Genes within the heterochromatin is not usually expressed. Histone acetylation promote transcription by opening up the chromatin structure. When acetyl groups are added to the histone tails, chromatin becomes less compact and dna becomes accessible. Dna methylation leads to condensed chromatin and reduced transcription. Removal of methyl groups can turn on genes. Control elements segments of noncoding dna that serve as binding sites for transcription factors. General transcription factors are required for transcription. Enhancer: distal control element; controls rate of gene expression; can increase binding of rna polymerase drastically. Activators that bind to enhancer greatly increase transcription. Some repressors bind to enhancers or other control elements and others interfere with the activators so they (cid:272)an"t (cid:271)ind to the enhan(cid:272)er. Repressors, rna polymerase, dna polymerase, dna ligase, primase, helicase.
