CHARACTERIZATION OF HUMAN CHROMOSOMAL CONSTITUTIVE HETEROCHROMATIN

2020 ◽  
Vol 53 (02) ◽  
pp. 08-11
Author(s):  
Aytakin Hasanova
Keyword(s):  
Satellite Dna ◽  
Constitutive Heterochromatin ◽  
Chromosome Breakage ◽  
Centromeric Heterochromatin ◽  
Crossing Over ◽  
Alpha Satellite ◽  
Alpha Satellite Dna ◽  
Chromosome Regions ◽  
Chromosome Disjunction

Heterochromatin of centromeric chromosome regions contains late replicating, largely repetitive DNA. It is suggested that heterochromatin participates in chromosome pairing, crossing-over and in chromosome disjunction control (1,3). Centromeric heterochromatin, a variety of heterochromatin, is a tightly packed form of DNA.Centromeric heterochromatin is a constituent in the formation ofactive centromeres in most higher-order organisms; the domain exists on both mitotic and interphase chromosomes. (4,5,6,8) Centromeric heterochromatin is usually formed on alpha satellite DNA in humans; however, there have been cases where centric heterochromatin and centromeres have formed on originally euchromatin domains lacking alpha satellite DNA; this usually happens as a result of a chromosome breakage event and the formed centromere is called a neocentromere.

scholarly journals Identification of a subdomain of CENP-B that is necessary and sufficient for localization to the human centromere.

1992 ◽  
Vol 116 (5) ◽  
pp. 1081-1093 ◽  
Author(s):  
A F Pluta ◽  
N Saitoh ◽  
I Goldberg ◽  
W C Earnshaw
Keyword(s):  
Satellite Dna ◽  
Centromeric Heterochromatin ◽  
Amino Terminus ◽  
Major Protein ◽  
Alpha Satellite ◽  
Alpha Satellite Dna ◽  
Human Centromere ◽  
Bacterial Enzyme

We have combined in vivo and in vitro approaches to investigate the function of CENP-B, a major protein of human centromeric heterochromatin. Expression of epitope-tagged deletion derivatives of CENP-B in HeLa cells revealed that a single domain less than 158 residues from the amino terminus of the protein is sufficient to localize CENP-B to centromeres. Centromere localization was abolished if as few as 28 amino acids were removed from the amino terminus of CENP-B. The centromere localization signal of CENP-B can function in an autonomous fashion, relocating a fused bacterial enzyme to centromeres. The centromere localization domain of CENP-B specifically binds in vitro to a subset of alpha-satellite DNA monomers. These results suggest that the primary mechanism for localization of CENP-B to centromeres involves the recognition of a DNA sequence found at centromeres. Analysis of the distribution of this sequence in alpha-satellite DNA suggests that CENP-B binding may have profound effects on chromatin structure at centromeres.

Genomic Organization of Human Centromeric Alpha Satellite DNA: Characterization of a Chromosome 17 Alpha Satellite Sequence

DNA ◽  
1987 ◽  
Vol 6 (4) ◽  
pp. 297-305 ◽  
Author(s):  
KONG H. CHOO ◽  
RUTH BROWN ◽  
GRAHAM WEBB ◽  
IAN W. CRAIG ◽  
R. GAY FILBY
Keyword(s):  
Satellite Dna ◽  
Genomic Organization ◽  
Chromosome 17 ◽  
Alpha Satellite ◽  
Satellite Sequence ◽  
Alpha Satellite Dna ◽  
Dna Characterization

scholarly journals Heat Stress Affects H3K9me3 Level at Human Alpha Satellite DNA Repeats

Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 663
Author(s):  
Isidoro Feliciello ◽  
Antonio Sermek ◽  
Željka Pezer ◽  
Maja Matulić ◽  
Đurđica Ugarković
Keyword(s):  
Heat Stress ◽  
Satellite Dna ◽  
Constitutive Heterochromatin ◽  
Dna Repeats ◽  
Alpha Satellite ◽  
Satellite Dnas ◽  
Alpha Satellite Dna ◽  
Expression Of Genes ◽  
Insertion Sites ◽  
H3k9me3 Level

Satellite DNAs are tandemly repeated sequences preferentially assembled into large arrays within constitutive heterochromatin and their transcription is often activated by stress conditions, particularly by heat stress. Bioinformatic analyses of sequenced genomes however reveal single repeats or short arrays of satellite DNAs dispersed in the vicinity of genes within euchromatin. Here, we analyze transcription of a major human alpha satellite DNA upon heat stress and follow the dynamics of “silent” H3K9me3 and “active” H3K4me2/3 histone marks at dispersed euchromatic and tandemly arranged heterochromatic alpha repeats. The results show H3K9me3 enrichment at alpha repeats upon heat stress, which correlates with the dynamics of alpha satellite DNA transcription activation, while no change in H3K4me2/3 level is detected. Spreading of H3K9me3 up to 1–2 kb from the insertion sites of the euchromatic alpha repeats is detected, revealing the alpha repeats as modulators of local chromatin structure. In addition, expression of genes containing alpha repeats within introns as well as of genes closest to the intergenic alpha repeats is downregulated upon heat stress. Further studies are necessary to reveal the possible contribution of H3K9me3 enriched alpha repeats, in particular those located within introns, to the silencing of their associated genes.

On the mode of evolution of alpha satellite DNA in human populations

1991 ◽  
Vol 33 (1) ◽  
pp. 42-48 ◽  
Author(s):  
B. Marçais ◽  
J. P. Charlieu ◽  
B. Allain ◽  
E. Brun ◽  
M. Bellis ◽  
...  
Keyword(s):  
Satellite Dna ◽  
Human Populations ◽  
Alpha Satellite ◽  
Alpha Satellite Dna
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