Everything involving DNA would have to deal with this chromatin structure
, Dang explained.
Evaluation of male fertility potential by Toluidine Blue test for sperm chromatin structure
CpG methylation, chromatin structure
and gene silencing--a three-way connection.
As mentioned above, H3K4me3 and H3K27me3 regulate an open or closed (unrepressed or repressed, resp.) chromatin structure
. However, these two different modifications of histone H3, which have opposite functions, may be present in the same promoter, referred to as bivalence .
Chen et al., "3D chromatin structures
of mature gametes and structural reprogramming during mammalian embryogenesis," Cell, vol.
Bull sperm head morphometry related to abnormal chromatin structure
Effects of formaldehyde (FA) exposure on chromatin structure
. (A) FA exposure increases chromatin accessibility.
(4) RAR/RXR forms a complex with transcriptional repressors, leading to formation of a closed chromatin structure
. Once RA binds to RAR, the repressor complex is replaced with the activator complex, inducing a relaxed chromatin structure
The lightly stained sperms were taken as having functional chromatin, while stained dark were considered as fragmented chromatin structure
. A total of 200 spermatozoa were assessed for each experimental extender.
These produce modifications in histone tails and chromatin structure
changes that lead to changes in the binding of transcription agents to their respective core promoter elements, resulting in the activation or suppression of special genes .
Epigenetics and Chromatin Structure
. In 1942, Conrad H.
There are two basic forms of chromatin structures
: (1) euchromatin is an open chromatin structure
in which DNA-binding proteins, such as transcription factors (TFs), are accessible to DNA, resulting in active transcription; and (2) heterochromatin is a condensed chromatin structure
that lacks accessibility to the transcriptional machinery, resulting in gene silencing.
Lysine acetylation of histones, transcription factors, and other proteins affect chromatin structure
, gene activity, and cell growth .
In fact, pRB plays an important role in chromosome dynamics and modulation of chromatin structure
. For example, pRB depletion alters chromatin structure
due to changes in epigenetic histone modifications, such as methylation and acetylation, which controls the status in G0/G1 cells  or heterochromatin region in the interphase cells [29, 30].
Early on in the process, two of the transcription factors, Isl1 and Lhx3, work in tandem, binding to the genome and beginning a cascade of events including changes to chromatin structure
and gene expression in the cells.