scholarly journals Replication-dependent histone isoforms: a new source of complexity in chromatin structure and function

2018 ◽  
Vol 46 (17) ◽  
pp. 8665-8678 ◽  
Author(s):  
Rajbir Singh ◽  
Emily Bassett ◽  
Arnab Chakravarti ◽  
Mark R Parthun
Keyword(s):  
Chromatin Structure ◽  
Structure And Function ◽  
And Function

scholarly journals Impact of DNA methylation on 3D genome structure

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Diana Buitrago ◽  
Mireia Labrador ◽  
Juan Pablo Arcon ◽  
Rafael Lema ◽  
Oscar Flores ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Chromatin Structure ◽  
Chromatin Condensation ◽  
Genome Structure ◽  
Dna Methyltransferases ◽  
Model System ◽  
Structure And Function ◽  
3D Genome ◽  
Cellular Machinery ◽  
And Function

AbstractDetermining the effect of DNA methylation on chromatin structure and function in higher organisms is challenging due to the extreme complexity of epigenetic regulation. We studied a simpler model system, budding yeast, that lacks DNA methylation machinery making it a perfect model system to study the intrinsic role of DNA methylation in chromatin structure and function. We expressed the murine DNA methyltransferases in Saccharomyces cerevisiae and analyzed the correlation between DNA methylation, nucleosome positioning, gene expression and 3D genome organization. Despite lacking the machinery for positioning and reading methylation marks, induced DNA methylation follows a conserved pattern with low methylation levels at the 5’ end of the gene increasing gradually toward the 3’ end, with concentration of methylated DNA in linkers and nucleosome free regions, and with actively expressed genes showing low and high levels of methylation at transcription start and terminating sites respectively, mimicking the patterns seen in mammals. We also see that DNA methylation increases chromatin condensation in peri-centromeric regions, decreases overall DNA flexibility, and favors the heterochromatin state. Taken together, these results demonstrate that methylation intrinsically modulates chromatin structure and function even in the absence of cellular machinery evolved to recognize and process the methylation signal.

scholarly journals Plant Histone HTB (H2B) Variants in Regulating Chromatin Structure and Function

Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1435
Author(s):  
Janardan Khadka ◽  
Anat Pesok ◽  
Gideon Grafi
Keyword(s):  
Arabidopsis Thaliana ◽  
Chromatin Structure ◽  
Developmental Stages ◽  
Histone Variants ◽  
Structure And Function ◽  
Core Histone ◽  
Histone H2b ◽  
Histone Proteins ◽  
Genes Encoding ◽  
And Function

Besides chemical modification of histone proteins, chromatin dynamics can be modulated by histone variants. Most organisms possess multiple genes encoding for core histone proteins, which are highly similar in amino acid sequence. The Arabidopsis thaliana genome contains 11 genes encoding for histone H2B (HTBs), 13 for H2A (HTAs), 15 for H3 (HTRs), and 8 genes encoding for histone H4 (HFOs). The finding that histone variants may be expressed in specific tissues and/or during specific developmental stages, often displaying specific nuclear localization and involvement in specific nuclear processes suggests that histone variants have evolved to carry out specific functions in regulating chromatin structure and function and might be important for better understanding of growth and development and particularly the response to stress. In this review, we will elaborate on a group of core histone proteins in Arabidopsis, namely histone H2B, summarize existing data, and illuminate the potential function of H2B variants in regulating chromatin structure and function in Arabidopsis thaliana.

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