Biology And Biomedical Sciences BIOL 2960 Lecture Notes - Lecture 32: Xist (Gene), Non-Coding Rna, X-Inactivation
23 Apr 2017
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Document Summary
Erasers: restore modified histone amino acids to unmodified form. Acetylation: loosens the chromatin to make it more accessible. Substitution of h on lysine with methyl group (ch3) Can be methylated 1, 2, or 3 times. Distinct protein binding determinants, so number of methyl groups depends on the protein being used -- more specific than acetylation. Positive charge remains, so the purpose is to serve as a recruitment site, no functional change. Chromatin is super dense, so rna pol can"t just go, it has to barge through the big tangle. The c-terminal domain (ctd tail of rna pol ii) must be phosphorylated by tfiih kinase to initiate transcription. The phosphorylated tail then provides a binding site for factors involved both in processing the transcript, and in regulating the activity of transcribed chromatin (chromatin modifiers). As such, it is an integrator or coordinator of the gene expression machinery.
