Centromere Assembly and Propagation

Abstract

Centromere assembly provides a unique example of how elaborate protein structures can be assembled onto DNA, independent of sequence, and then stably propagated through numerous cell divisions. Here, we review the possible epigenetic strategies that organisms ranging from yeast to human use to assemble and propagate active centromeres.

GATA simple sequence repeats function as enhancer blocker boundaries

“…Briefly, 0-to 12-h-old embryos were dechorionated in 50% bleach (sodium hypochlorite), washed and fixed in heptane saturated with 25% glutaraldehyde for 20 min. The fixed embryos were washed with PBSTx (PBS þ 0.3% Triton X 100) thoroughly followed by a single wash with pre-warmed X-gal staining buffer (7.2 mM Na 2 HPO 4 , 2.8 mM NaH 2 PO 4 , 150 mM NaCl, 1 mM MgCl 2 , 3 mM K 3 [Fe(CN) 6 ], 3 mM K 4 [Fe(CN) 6 ]). The embryos were then incubated in staining buffer containing 1% X-gal (Sigma) till good staining pattern develops (2-10 h).…”

“…Much of this non-coding DNA consists of a variety of repetitive DNA including transposable elements (TEs) and simple sequence repeats (SSRs). Certain repetitive sequences have been implicated in chromatin-mediated transcriptional regulation, chromosome organization, imprinting, chromatin domain boundary function and complex nuclear features such as heterochromatin, telomeres and nucleolar organization [1][2][3][4][5][6][7][8] . SSRs, on the other hand, have not been directly implicated in such regulatory roles although this class of DNA has also accumulated in complex genomes, particularly in vertebrates 9,10 .…”

Transgenerational Epigenetic Inheritance: Prevalence, Mechanisms, and Implications for the Study of Heredity and Evolution

“…In eukaryotes, important variations in chromatin are associated with histones, the proteins that make up the nucleosome core around which DNA is wrapped. The dynamic nature of histones, their variability, and their association with every conceivable cellular function (see Berger 2007;Groth et al 2007;Blasco 2007;Morris and Moazed 2007) makes understanding the inheritance of their specific structure and organization both challenging and urgent. Several models of this process have been constructed, and according to all of them, the nucleosome variants and the post-transcriptional modifications (PTMs) of the parental nucleosomes are used as blueprints for the restoration of the same nucleosome configuration.…”

Genomewide Screen for Negative Regulators of Sirtuin Activity inSaccharomyces cerevisiaeReveals 40 Loci and Links to Metabolism

“…The Sir complex appears to spread laterally from its nucleation points (Morris and Moazed 2007). This is thought to be accomplished through a cycle of histonetail deacetylation by Sir2 that enables binding of additional copies of the Sir complex through the histone-tail binding sites in Sir3 and Sir4, whose binding to nucleosomes is inhibited by histone-tail acetylation.…”