BIOL 483 Lecture Notes - Lecture 45: Histone Deacetylase, Methylation, Schizosaccharomyces Pombe
Chromatin in silenced regions: regular spaced nucleosome arrays, presence of certain histone modificatiosn (h3k9me, presence of dna methylation, bordered by boundary elements, presence of non histone proteins (hp1, sirtuins, pcg, telosome) Key silencing regions = telomeres, centromeres // can also be silenced by silent mating type loci. Yeast normally grow as haploids, but if their envrionment situation isn"t ideal for survival, yeast will swap to silent mating type loci. When silent mating type loci induced, yeast can mate and give rise to diff structures that can withstand bad situations better than haploid yeast does. Heterochromatin rarely needs to go into silent mating type loci mode, it"s only triggered when regions become activated for mating to allow for survival in a bad environment. In s. cerevisiae or s. pombe as mating is important for low nutrient conditions. Haploid cells (normal yeast cells) have 1 active mating type locus (mat, mat1) When needed, a mating type switch can occur.