Genetic Remodeling and Transcriptional Remodeling of Subtelomeric Heterochromatin Are Different†

Biochemistry ◽  
2002 ◽  
Vol 41 (15) ◽  
pp. 4901-4910 ◽  
Author(s):  
Sabrina Venditti ◽  
Glauco Di Stefano ◽  
Manuela D'Eletto ◽  
Ernesto Di Mauro
Keyword(s):  
Subtelomeric Heterochromatin

scholarly journals Trans-Silencing by P Elements Inserted in Subtelomeric Heterochromatin Involves the Drosophila Polycomb Group Gene, Enhancer of zeste

Genetics ◽  
1998 ◽  
Vol 149 (4) ◽  
pp. 1839-1855 ◽  
Author(s):  
Siobhan E Roche ◽  
Donald C Rio
Keyword(s):  
Transcriptional Repression ◽  
Protein Product ◽  
Polycomb Group ◽  
P Element ◽  
Subtelomeric Heterochromatin ◽  
P Elements ◽  
Enhancer Of Zeste ◽  
Gene Enhancer ◽  
Associated Sequences ◽  
Polycomb Group Gene

AbstractDrosophila P-element transposition is regulated by a maternally inherited state known as P cytotype. An important aspect of P cytotype is transcriptional repression of the P-element promoter. P cytotype can also repress non-P-element promoters within P-element ends, suggesting that P cytotype repression might involve chromatin-based transcriptional silencing. To learn more about the role of chromatin in P cytotype repression, we have been studying the P strain Lk-P(1A). This strain contains two full-length P elements inserted in the heterochromatic telomere-associated sequences (TAS elements) at cytological location 1A. Mutations in the Polycomb group gene (Pc-G gene), Enhancer of zeste (E(z)), whose protein product binds at 1A, resulted in a loss of Lk-P(1A) cytotype control. E(z) mutations also affected the trans-silencing of heterologous promoters between P-element termini by P-element transgenes inserted in the TAS repeats. These data suggest that pairing interactions between P elements, resulting in exchange of chromatin structures, may be a mechanism for controlling the expression and activity of P elements.

scholarly journals Ccq1–Raf2 interaction mediates CLRC recruitment to establish heterochromatin at telomeres

2021 ◽  
Vol 4 (11) ◽  
pp. e202101106
Author(s):  
Shaohua Shi ◽  
Yuanze Zhou ◽  
Yanjia Lu ◽  
Hong Sun ◽  
Jing Xue ◽  
...  
Keyword(s):  
Protein Complexes ◽  
Dominant Role ◽  
Specific Interaction ◽  
Feedback Mechanism ◽  
Subtelomeric Heterochromatin ◽  
Shelterin Complex ◽  
Repressor Complex ◽  
Telomeric Heterochromatin ◽  
Positive Feedback Mechanism ◽  
Heterochromatin Assembly

Telomeres, highly ordered DNA-protein complexes at eukaryotic linear chromosome ends, are specialized heterochromatin loci conserved among eukaryotes. In Schizosaccharomyces pombe, the shelterin complex is important for subtelomeric heterochromatin establishment. Despite shelterin has been demonstrated to mediate the recruitment of the Snf2/histone deacetylase–containing repressor complex (SHREC) and the Clr4 methyltransferase complex (CLRC) to telomeres, the mechanism involved in telomeric heterochromatin assembly remains elusive due to the multiple functions of the shelterin complex. Here, we found that CLRC plays a dominant role in heterochromatin establishment at telomeres. In addition, we identified a series of amino acids in the shelterin subunit Ccq1 that are important for the specific interaction between Ccq1 and the CLRC subunit Raf2. Finally, we demonstrated that the Ccq1–Raf2 interaction is essential for the recruitment of CLRC to telomeres, that contributes to histone H3 lysine 9 methylation, nucleosome stability and the shelterin-chromatin association, promoting a positive feedback mechanism for the nucleation and spreading of heterochromatin at subtelomeres. Together, our findings provide a mechanistic understanding of subtelomeric heterochromatin assembly by shelterin-dependent CLRC recruitment to chromosomal ends.

scholarly journals Analysis of subtelomeric heterochromatin in the Drosophila minichromosome Dp1187 by single P element insertional mutagenesis.

Genetics ◽  
1992 ◽  
Vol 132 (3) ◽  
pp. 737-753 ◽  
Author(s):  
G H Karpen ◽  
A C Spradling
Keyword(s):  
Insertional Mutagenesis ◽  
Position Effect ◽  
P Element ◽  
Centromeric Heterochromatin ◽  
Small Subset ◽  
Position Effect Variegation ◽  
Subtelomeric Heterochromatin ◽  
P Elements ◽  
Salivary Gland Cells ◽  
And Function

Abstract We investigated whether single P element insertional mutagenesis could be used to analyze heterochromatin within the Drosophila minichromosome Dp1187. Forty-five insertions of the P[lacZ,rosy+] element onto Dp1187 (recovered among 7,825 transpositions) were highly clustered. None was recovered in centromeric heterochromatin, but 39 occurred about 40 kb from the distal telomere within a 4.7-kb hotspot containing tandem copies of a novel 1.8-kb repetitive DNA sequence. The DNA within and distal to this region lacked essential genes and displayed several other properties characteristic of heterochromatin. The rosy+ genes within the inserted transposons were inhibited by position-effect variegation, and the subtelomeric region was underrepresented in polytene salivary gland cells. These experiments demonstrated that P elements preferentially transpose into a small subset of heterochromatic sites, providing a versatile method for studying the structure and function of these chromosome regions. This approach revealed that a Drosophila chromosome contains a large region of subtelomeric heterochromatin with specific structural and genetic properties.

scholarly journals Human telomeres replicate using chromosome-specific, rather than universal, replication programs

2012 ◽  
Vol 197 (2) ◽  
pp. 253-266 ◽  
Author(s):  
William C. Drosopoulos ◽  
Settapong T. Kosiyatrakul ◽  
Zi Yan ◽  
Simone G. Calderano ◽  
Carl L. Schildkraut
Keyword(s):  
Single Molecule ◽  
Embryonic Stem ◽  
Cell Types ◽  
Es Cell ◽  
Site Location ◽  
Subtelomeric Heterochromatin ◽  
Basic Features ◽  
Different Cell Types ◽  
Single Molecule Analysis ◽  
Individual Human

Telomeric and adjacent subtelomeric heterochromatin pose significant challenges to the DNA replication machinery. Little is known about how replication progresses through these regions in human cells. Using single molecule analysis of replicated DNA (SMARD), we delineate the replication programs—i.e., origin distribution, termination site location, and fork rate and direction—of specific telomeres/subtelomeres of individual human chromosomes in two embryonic stem (ES) cell lines and two primary somatic cell types. We observe that replication can initiate within human telomere repeats but was most frequently accomplished by replisomes originating in the subtelomere. No major delay or pausing in fork progression was detected that might lead to telomere/subtelomere fragility. In addition, telomeres from different chromosomes from the same cell type displayed chromosome-specific replication programs rather than a universal program. Importantly, although there was some variation in the replication program of the same telomere in different cell types, the basic features of the program of a specific chromosome end appear to be conserved.

scholarly journals The evolution of African great ape subtelomeric heterochromatin and the fusion of human chromosome 2

2012 ◽  
Vol 22 (6) ◽  
pp. 1036-1049 ◽  
Author(s):  
Mario Ventura ◽  
Claudia R. Catacchio ◽  
Saba Sajjadian ◽  
Laura Vives ◽  
Peter H. Sudmant ◽  
...  
Keyword(s):  
Human Chromosome ◽  
Chromosome 2 ◽  
Great Ape ◽  
Subtelomeric Heterochromatin

scholarly journals Corrigendum: The evolution of African great ape subtelomeric heterochromatin and the fusion of human chromosome 2

2017 ◽  
Vol 27 (9) ◽  
pp. 1621.1-1621.1
Author(s):  
Mario Ventura ◽  
Claudia R. Catacchio ◽  
Saba Sajjadian ◽  
Laura Vives ◽  
Peter H. Sudmant ◽  
...  
Keyword(s):  
Human Chromosome ◽  
Chromosome 2 ◽  
Great Ape ◽  
Subtelomeric Heterochromatin
Sign in / Sign up

Export Citation Format

Share Document