BIOL 483 Lecture Notes - Lecture 47: Chromosomal Translocation, Telomere, Transfer Rna
Document Summary
Enzymes that remove hp1 (nb hp1 helps with compaction: h3k9me demethylase, normally associated with outside regions of heterochromatin on boundary between heterochromatin -> euchromatin, in heterochromatin, this enzyme is inactive, h3s10ph. Recruitment of hp1 can be regulated via this methyl phospho switch. Enzyme that adds h3k9me3 and hp1 contribute to spreading. Heterochromatin can spread further to euchromatin but it doesn"t because of an insulator/boundary that prevents spreading. Boundary = region with active transcription and acetylation on various residues, but no. Heterochromatin is adjacent to euchromatin and it could spread to convert euchromatin. > heterochromatin, but boundary prevents this from happening. At boundary: high level of hat -> acetylation, h3k4me (active mark, tf3c (binding site for factors that activate trna expression, active region of genome) Lots of activating histone modifications at boundary and regions devoid of nucleosomes/ high nucleosome turnover at boundary. Boundaries were discovered when they found higher than expected trans gene rates.
