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.

scholarly journals CENP-C binds the alpha-satellite DNA in vivo at specific centromere domains

2002 ◽  
Vol 115 (11) ◽  
pp. 2317-2327 ◽  
Author(s):  
Valeria Politi ◽  
Giovanni Perini ◽  
Stefania Trazzi ◽  
Artem Pliss ◽  
Ivan Raska ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Satellite Dna ◽  
Alpha Satellite ◽  
Alpha Satellite Dna ◽  
Human Centromere ◽  
Ultrastructural Characterization ◽  
First Time

CENP-C is a fundamental component of the centromere, highly conserved among species and necessary for the proper assembly of the kinetochore structure and for the metaphase-anaphase transition. Although CENP-C can bind DNA in vitro,the identification of the DNA sequences associated with it in vivo and the significance of such an interaction have been, until now, elusive. To address this problem we took advantage of a chromatin-immunoprecipitation procedure and applied this technique to human HeLa cells. Through this approach we could establish that: (1) CENP-C binds the alpha-satellite DNA selectively; (2) the CENP-C region between amino acids 410 and 537, previously supposed to contain a DNA-binding domain, is indeed required to perform such a function in vivo;and (3) the profile of the alpha-satellite DNA associated with CENP-C is essentially identical to that recognized by CENP-B. However, further biochemical and ultrastructural characterization of CENP-B/DNA and CENP-C/DNA complexes, relative to their DNA components and specific spatial distribution in interphase nuclei, surprisingly reveals that CENP-C and CENP-B associate with the same types of alpha-satellite arrays but in distinct non-overlapping centromere domains. Our results, besides extending previous observations on the role of CENP-C in the formation of active centromeres, show, for the first time, that CENP-C can associate with the centromeric DNA sequences in vivo and, together with CENP-B, defines a highly structured organization of the alpha-satellite DNA within the human centromere.

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 Repetitive Fragile Sites: Centromere Satellite DNA As a Source of Genome Instability in Human Diseases

Genes ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 615 ◽  
Author(s):  
Elizabeth M. Black ◽  
Simona Giunta
Keyword(s):  
Satellite Dna ◽  
Genome Instability ◽  
Fragile Sites ◽  
Special Focus ◽  
Alpha Satellite ◽  
Chromosomal Locus ◽  
Alpha Satellite Dna ◽  
Human Centromere ◽  
Repetitive Nature ◽  
Human Genome Assembly

Maintenance of an intact genome is essential for cellular and organismal homeostasis. The centromere is a specialized chromosomal locus required for faithful genome inheritance at each round of cell division. Human centromeres are composed of large tandem arrays of repetitive alpha-satellite DNA, which are often sites of aberrant rearrangements that may lead to chromosome fusions and genetic abnormalities. While the centromere has an essential role in chromosome segregation during mitosis, the long and repetitive nature of the highly identical repeats has greatly hindered in-depth genetic studies, and complete annotation of all human centromeres is still lacking. Here, we review our current understanding of human centromere genetics and epigenetics as well as recent investigations into the role of centromere DNA in disease, with a special focus on cancer, aging, and human immunodeficiency–centromeric instability–facial anomalies (ICF) syndrome. We also highlight the causes and consequences of genomic instability at these large repetitive arrays and describe the possible sources of centromere fragility. The novel connection between alpha-satellite DNA instability and human pathological conditions emphasizes the importance of obtaining a truly complete human genome assembly and accelerating our understanding of centromere repeats’ role in physiology and beyond.

A functional neo-centromere formed through activation of a latent human centromere and consisting of non-alpha-satellite DNA

1997 ◽  
Vol 16 (2) ◽  
pp. 144-153 ◽  
Author(s):  
Desirée du Sart ◽  
Michael R. Cancilla ◽  
Elizabeth Earle ◽  
Jen-i Mao ◽  
Richard Saffery ◽  
...  
Keyword(s):  
Satellite Dna ◽  
Alpha Satellite ◽  
Alpha Satellite Dna ◽  
Human Centromere

scholarly journals Expression of laminin γ 1 cultured hepatocytes involves repeated CTC and GC elements in the LAMC1 promoter

1996 ◽  
Vol 313 (3) ◽  
pp. 745-752 ◽  
Author(s):  
Françoise LEVAVASSEUR ◽  
Jocelyne LIÉTARD ◽  
Kohei OGAWA ◽  
Nathalie THÉRET ◽  
Peter D. BURBELO ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Hepatoma Cell ◽  
Primary Cultures ◽  
Regulatory Elements ◽  
Hepatoma Cells ◽  
Basement Membranes ◽  
Major Protein ◽  
Cultured Hepatocytes

Laminin γ1 chain is present in all basement membranes and is expressed at high levels in various diseases, such as hepatic fibrosis. We have identified cis- and trans-acting elements involved in the regulation of this gene in normal rat liver, as well as in hepatocyte primary cultures and hepatoma cell lines. Northern-blot analyses showed that laminin γ1 mRNA was barely detectable in freshly isolated hepatocytes and expressed at high levels in hepatocyte primary cultures, as early as 4 h after liver dissociation. Actinomycin D and cycloheximide treatment in vivo and in vitro indicated that laminin γ1 overexpression in cultured hepatocytes was under the control of transcriptional mechanisms. Transfection of deletion mutants of the 5´ flanking region of murine LAMC1 gene in hepatoma cells that constitutively express laminin γ1 indicated that regulatory elements were located between -594 bp and -94 bp. This segment included GC- and CTC-containing motifs. Gel-shift analyses showed that two complexes were resolved with different affinity for the CTC sequence depending on the location of the GC box. The pattern of complex formation with nuclear factors from freshly isolated and cultured hepatocytes was different from that obtained with total liver and similar to that with hepatoma cells. Southwestern analysis indicated that several polypeptides bound the CTC-rich sequence. Affinity chromatography demonstrated that a Mr 60000 polypeptide was a major protein binding to the CTC motif. This polypeptide is probably involved in the transcriptional activation of various proto-oncogenes and extracellular matrix genes that are expressed at high levels in both hepatoma cells and early hepatocyte cultures.

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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