BCHM 4116 1st Edition Lecture 26 Outline of Last Lecture I The structure and function of RNA polymerase II the mRNA synthesizing RNA polymerase II Transcription regulation in eukaryotes including Outline of Current Lecture I Transcription initiation by RNA pol II requires TBP and GTFs Current Lecture Chapter 29 Transcription and Regulation of Gene Expression cont 3 i Transcription initiation by RNA pol II requires TBP and GTFs 1 The general transcription factors GTFs a GTFs TFIIA TFIIB TFIID TFIIF TFIIH TFIIS b TFIID TBP c TFIIA stabilizes TFIID and TATA box d TFIIB recruits preinitiation complex PIC to promoter positioning RNA pol active site over promoter e TFIIE TFIIF enhance promoter PIC interaction f TFIIH helicase aids in creating transcription bubble 2 Mediators a Bridge b w enhancers transcription co activators to RNA pol at the promoter b Ultimate regulator of transcription c Acts as repressor and activator of transcription 3 Alleviating the repression due to nucleosomes a Relief from repression imposed by chromatin structure requires factors that can reorganize chromatin alter nucleosomes so that promoters become accessible to transcriptional machinery i Chromatin remodeling complexes 1 Mediate ATP dependent conformational noncovalent changes in nucleosome structures 2 Nucleic acid stimulated multisubunit ATPase ii Histone modifying enezymes These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 1 Introduce covalent modifications into Nterminal tails of histone a 1 Diminish DNA histone associations via disruption of electrostatic interactions b 2 Introduce subsititutaions that can recruit binding of new protein participants through protein protein interactions b Histone acetyl transferases HATs i Acetylation of amino group on lysine residues in histone tails ii N acetylation suppresses positive charge in histone tails diminishing their interaction w negatively charged DNA c Transcription regulation i Phosphorylation of Ser residues ii Methylation of Lys residues
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