Histone Variants and Histone Modifications in Neurogenesis

2020 ◽  
Vol 30 (11) ◽  
pp. 869-880
Author(s):  
Mengtian Zhang ◽  
Jinyue Zhao ◽  
Yuqing Lv ◽  
Wenwen Wang ◽  
Chao Feng ◽  
...  
Keyword(s):  
Histone Modifications ◽  
Histone Variants

A haploid affair: core histone transitions during spermatogenesis

2003 ◽  
Vol 81 (3) ◽  
pp. 131-140 ◽  
Author(s):  
John D Lewis ◽  
D Wade Abbott ◽  
Juan Ausió
Keyword(s):  
Histone Modifications ◽  
Chromatin Structure ◽  
Critical Role ◽  
Diploid Cell ◽  
Histone Variants ◽  
Histone H4 ◽  
Dna Compaction ◽  
Dynamic Composition ◽  
Shed Light

The process of meiosis reduces a diploid cell to four haploid gametes and is accompanied by extensive recombination. Thus, the dynamics of chromatin during meiosis are significantly different than in mitotic cells. As spermatogenesis progresses, there is a widespread reorganization of the haploid genome followed by extensive DNA compaction. It has become increasingly clear that the dynamic composition of chromatin plays a critical role in the activities of enzymes and processes that act upon it. Therefore, an analysis of the role of histone variants and modifications in these processes may shed light upon the mechanisms involved and the control of chromatin structure in general. Histone variants such as histone H3.3, H2AX, and macroH2A appear to play key roles in the various stages of spermiogenesis, in addition to the specifically modulated acetylation of histone H4 (acH4), ubiquitination of histones H2A and H2B (uH2A, uH2B), and phosphorylation of histone H3 (H3p). This review will examine recent discoveries concerning the role of histone modifications and variants during meiosis and spermatogenesis.Key words: histone variants, histone modifications, chromatin structure, meiosis.

Aging, cellular senescence and cancer: epigenetic alterations and nuclear remodeling

2019 ◽  
pp. 238-253
Author(s):  
John C. Lucchesi
Keyword(s):  
Histone Modifications ◽  
Cellular Senescence ◽  
Aging Process ◽  
Nuclear Architecture ◽  
Gene Mutations ◽  
Histone Variants ◽  
Premature Aging ◽  
Model Organisms ◽  
Premature Aging Syndromes ◽  
Nuclear Remodeling

Epigenetic modifications correlated with aging and oncogenesis are changes in the pattern of DNA methylation and of histone modifications, and changes in the level of histone variants (H3.3, macroH2A, H2A.Z) and gene mutations. The sirtuins are a set of highly conserved protein deacetylases of particular significance to the aging process. Many cancer types are found to carry mutations in chromatin-modifying genes such as those encoding methyl or acetyl transferases, affecting the histone modifications of promoters and enhancers. The aging process and oncogenesis present a number of changes in the nuclear architecture. Mutations in the lamina-coding genes lead to premature aging syndromes. Mutations in remodeling complexes are found in different cancers. Modifications that affect the architectural protein binding sites at topologically associating domain (TAD) borders can cause the merging of neighboring TADs. The levels of short non-coding RNAs (sncRNAs) are altered in model organisms and are associated with cancer. Changes in the position of chromosome territories often occur in tumor cells. Nevertheless, cellular senescence, due mostly to the absence of telomerase, represents a mechanism of tumor suppression.

Histone variants and histone modifications: A structural perspective

2001 ◽  
Vol 79 (6) ◽  
pp. 693-708 ◽  
Author(s):  
Juan Ausió ◽  
D Wade Abbott ◽  
Xiaoying Wang ◽  
Susan C Moore
Keyword(s):  
Recent Work ◽  
Histone Modifications ◽  
Posttranslational Modifications ◽  
Structural Component ◽  
Functional Role ◽  
Short Range ◽  
Histone Variants ◽  
Current State ◽  
Functional Implications ◽  
Different Levels

In this review, we briefly analyze the current state of knowledge on histone variants and their posttranslational modifications. We place special emphasis on the description of the structural component(s) defining and determining their functional role. The information available indicates that this histone "variability" may operate at different levels: short-range "local" or long-range "global", with different functional implications. Recent work on this topic emphasizes an earlier notion that suggests that, in many instances, the functional response to histone variability is possibly the result of a synergistic structural effect.Key words: histone variants, posttranslational modifications, chromatin.

scholarly journals Transcriptionally Active Chromatin—Lessons Learned from the Chicken Erythrocyte Chromatin Fractionation

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1354
Author(s):  
Tasnim H. Beacon ◽  
James R. Davie
Keyword(s):  
Histone Modifications ◽  
Histone Variants ◽  
Structural Features ◽  
Lessons Learned ◽  
Open Chromatin ◽  
Chicken Erythrocyte ◽  
Histone H4 ◽  
Active Chromatin ◽  
Chromatin Structural ◽  
Chromatin Fractionation

The chicken erythrocyte model system has been valuable to the study of chromatin structure and function, specifically for genes involved in oxygen transport and the innate immune response. Several seminal features of transcriptionally active chromatin were discovered in this system. Davie and colleagues capitalized on the unique features of the chicken erythrocyte to separate and isolate transcriptionally active chromatin and silenced chromatin, using a powerful native fractionation procedure. Histone modifications, histone variants, atypical nucleosomes (U-shaped nucleosomes) and other chromatin structural features (open chromatin) were identified in these studies. More recently, the transcriptionally active chromosomal domains in the chicken erythrocyte genome were mapped by combining this chromatin fractionation method with next-generation DNA and RNA sequencing. The landscape of histone modifications relative to chromatin structural features in the chicken erythrocyte genome was reported in detail, including the first ever mapping of histone H4 asymmetrically dimethylated at Arg 3 (H4R3me2a) and histone H3 symmetrically dimethylated at Arg 2 (H3R2me2s), which are products of protein arginine methyltransferases (PRMTs) 1 and 5, respectively. PRMT1 is important in the establishment and maintenance of chicken erythrocyte transcriptionally active chromatin.

Epigenetic chromatin changes and the transcription cycle

2019 ◽  
pp. 57-68
Author(s):  
John C. Lucchesi
Keyword(s):  
Rna Polymerase Ii ◽  
Histone Modifications ◽  
Histone Variants ◽  
Gene Promoters ◽  
Chromatin Remodelers ◽  
Dna Binding Sites ◽  
Core Histones ◽  
Transcript Elongation ◽  
Pioneer Factors ◽  
Histone Octamers

In order to allow transcription to occur, the association of DNA with histone octamers and the compacted physical state of the chromatin fiber must be modified by the opportunistic binding of pioneer transcription factors to their cognate DNA binding sites. Once bound, pioneer factors recruit chromatin remodelers and histone-modifying enzymes for the purpose of repositioning nucleosomes and exposing regulatory regions (enhancers and gene promoters) to the components necessary for the initiation of transcription. Histone modifications, such as acetylation, methylation and ubiquitination, and the dynamic phosphorylation of specific amino acids on the major RNA polymerase II subunit activate transcription and attract the factors necessary to eliminate the pausing that normally occurs soon after initiation. Further histone modifications and the replacement of certain core histones by histone variants facilitate transcript elongation and termination. Two additional major epigenetic modifications that impact the process of transcription consist of the action of non-coding RNAs and DNA methylation.

Dynamic Profiles and Transcriptional Preferences of Histone Modifications During Spermiogenesis

Endocrinology ◽  
2020 ◽  
Vol 162 (1) ◽  
Author(s):  
Yinchuan Li ◽  
Panpan Mi ◽  
Xue Chen ◽  
Jiabao Wu ◽  
Weibing Qin ◽  
...  
Keyword(s):  
Histone Modifications ◽  
Genetic Material ◽  
Transcriptome Profiling ◽  
Histone Variants ◽  
Transcriptome Profile ◽  
Morphological Alterations ◽  
Transcriptional Dynamics ◽  
Epigenetic Modifier ◽  
The Impact ◽  
Encoding Genes

Abstract During spermiogenesis, extensive histone modifications take place in developing haploid spermatids besides morphological alterations of the genetic material to form compact nuclei. Better understanding on the overall transcriptional dynamics and preferences of histones and enzymes involved in histone modifications may provide valuable information to dissect the epigenetic characteristics and unique chromatin status during spermiogenesis. Using single-cell RNA-Sequencing, the expression dynamics of histone variants, writers, erasers, and readers of histone acetylation and methylation, as well as histone phosphorylation, ubiquitination, and chaperones were assessed through transcriptome profiling during spermiogenesis. This approach provided an unprecedented panoramic perspective of the involving genes in epigenetic modifier/histone variant expression during spermiogenesis. Results reported here revealed the transcriptional ranks of histones, histone modifications, and their readers during spermiogenesis, emphasizing the unique preferences of epigenetic regulation in spermatids. These findings also highlighted the impact of spermatid metabolic preferences on epigenetic modifications. Despite the observed rising trend on transcription levels of all encoding genes and histone variants, the transcriptome profile of genes in histone modifications and their readers displayed a downward expression trend, suggesting that spermatid nuclei condensation is a progressive process that occurred in tandem with a gradual decrease in overall epigenetic activity during spermiogenesis.

Epigenetic analysis of human embryonic carcinoma cells during retinoic acid-induced neural differentiation

2010 ◽  
Vol 88 (3) ◽  
pp. 527-538 ◽  
Author(s):  
Maryam Shahhoseini ◽  
Adeleh Taei ◽  
Narges Zare Mehrjardi ◽  
Ghasem Hosseini Salekdeh ◽  
Hossein Baharvand
Keyword(s):  
Cell Culture ◽  
Stem Cell ◽  
Retinoic Acid ◽  
Histone Modifications ◽  
Chromatin Structure ◽  
Neural Differentiation ◽  
Stem Cell Differentiation ◽  
Histone Variants ◽  
Global Changes ◽  
Dependent Manner

Differentiation of stem cells from a pluripotent to a committed state involves global changes in genome expression patterns, critically determined by chromatin structure and interactions of chromatin-binding proteins. The dynamics of chromatin structure are tightly regulated by multiple epigenetic mechanisms such as histone modifications and the incorporation of histone variants. In the current work, we induced neural differentiation of a human embryonal carcinoma stem cell line, NTERA2/NT2, by retinoic acid (RA) treatment, primarily according to two different methods of adherent cell culture (rosette formation) and suspension cell culture (EB formation) conditions, and histone modifications and variations were compared through these processes. Western blot analysis of histone extracts showed significant changes in the acetylation and methylation patterns of histone H3, and expression level of the histone variant H2A.Z, after RA treatment in both protocols. Using chromatin immunoprecipitation (ChIP) coupled with real-time PCR, it was shown that these epigenetic changes occurred on the regulatory regions of 4 marker genes (Oct4, Nanog, Nestin, and Pax6) in a culture condition dependent manner. This report demonstrates the dynamic interplay of histone modification and variation in regulating the gene expression profile, during stem cell differentiation and under different culture conditions.

Sign in / Sign up

Export Citation Format

Share Document