Germline chromatin

Schaner, Christine E; Kelly, William G.

doi:10.1895/wormbook.1.73.1

Cited by 73 publications

(93 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…apoptotic nuclei/gonad 0 1 2 3 4 5 6 N Mean SD SE mean transcriptional activation (Schaner and Kelly 2006), as well as XND-1 (Wagner et al 2010)]. To determine whether HIM-5 is also underrepresented on the X, hermaphrodite germlines were costained with anti-XND-1 and anti-HIM-5 antibodies.…”

Section: Table 3 Apoptosis Analysis With Syto 12mentioning

confidence: 99%

“…In contrast, modifications associated with transcriptional activation are predominantly found on the autosomes (Schaner and Kelly 2006). We previously showed that xnd-1 could be suppressed by mutations in mes-2 in which X chromosome gene silencing does not occur, raising the possibility that silencing of the X blocks crossover formation on this chromosome (Wagner et al 2010).…”

Section: Him-5 Is Suppressed By Changes In X Chromosome Architecturementioning

confidence: 99%

“…The X chromosome is transcriptionally repressed throughout most of germline development (Kelly et al 2002) and histone modifications associated with closed and open chromatin configurations are enriched on the X and autosomes, respectively (Schaner and Kelly 2006). Furthermore, a number of mutations differentially affect crossover (CO) frequencies on the X chromosome vs. the autosomes.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Crossover Distribution and Frequency Are Regulated by him-5 in Caenorhabditis elegans

et al. 2012

View full text Add to dashboard Cite

Mutations in the him-5 gene in Caenorhabditis elegans strongly reduce the frequency of crossovers on the X chromosome, with lesser effects on the autosomes. him-5 mutants also show a change in crossover distribution on both the X and autosomes. These phenotypes are accompanied by a delayed entry into pachytene and premature desynapsis of the X chromosome. The nondisjunction, progression defects and desynapsis can be rescued by an exogenous source of double strand breaks (DSBs), indicating that the role of HIM-5 is to promote the formation of meiotic DSBs. Molecular cloning of the gene shows that the inferred HIM-5 product is a highly basic protein of 252 amino acids with no clear orthologs in other species, including other Caenorhabditis species. Although him-5 mutants are defective in segregation of the X chromosome, HIM-5 protein localizes preferentially to the autosomes. The mutant phenotypes and localization of him-5 are similar but not identical to the results seen with xnd-1, although unlike xnd-1, him-5 has no apparent effect on the acetylation of histone H2A on lysine 5 (H2AacK5). The localization of HIM-5 to the autosomes depends on the activities of both xnd-1 and him-17 allowing us to begin to establish pathways for the control of crossover distribution and frequency.C ROSSING over between homologous chromosomes during meiosis promotes genetic diversity by creating new combinations of alleles over generations. Crossovers also create physical connections between the homologs that ensure their proper alignment on the meiotic spindle and subsequent apposite segregation. Accordingly, homologous chromosomes require a crossover to prevent nondisjunction, and each of the events of meiosis I functions to promote this exchange.A necessary early step in crossing over is the SPO11-dependent formation of double strand breaks (DSBs) (Keeney et al. 1997). In Saccharomyces cerevisiae, at least nine other proteins interact with SPO11 to regulate the recruitment and activation of SPO11 (Keeney and Neale 2006). These proteins that regulate the action of SPO11 are not highly conserved at the amino acid level, but recent studies have identified functional homologs of several of these components in mice (Cole et al. 2010;Kumar et al. 2010). Nevertheless, relatively little is known about the regulation of the SPO11 machinery in organisms other than S. cerevisiae.Meiotic breaks occur preferentially in regions of open chromatin structure known as hotspots (Ohta et al. 1994;Wu and Lichten 1994). The pattern of crossovers and the recombination frequency vary among different chromosomes even within a species. One of the most distinctive patterns is seen in Caenorhabditis elegans, where the recombination rate on autosomes is repressed in the central region of each autosome, which contains a tight central cluster of genes. Instead crossovers occur preferentially on the chromosome arms where genes are widely spaced (Barnes et al. 1995). The X chromosome has a different pattern, in which genes are more uniformly spaced and...

show abstract

Section: Table 3 Apoptosis Analysis With Syto 12mentioning

confidence: 99%

Section: Him-5 Is Suppressed By Changes In X Chromosome Architecturementioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Crossover Distribution and Frequency Are Regulated by him-5 in Caenorhabditis elegans

et al. 2012

View full text Add to dashboard Cite

show abstract

“…To equalize the expression of X-linked genes in the two sexes, transcription from both X chromosomes is partially repressed in somatic cells of hermaphrodites by a dosage compensation complex related to mitotic condensin (Meyer 2010). In both XX and XO worms, the X chromosomes are largely silenced in germ cells by a distinct and less-well-understood machinery than used in the soma (Schaner and Kelly 2006). C. elegans does not have a defined centromeric locus on each chromosome; instead, the chromosomes are holocentric, with centromeric function distributed along the length of each chromosome (Albertson and Thomson 1982;Maddox et al 2004).…”

mentioning

confidence: 99%

Broad chromosomal domains of histone modification patterns in C. elegans

Liu¹,

Rechtsteiner²,

Egelhofer³

et al. 2010

Genome Res.

269

331

View full text Add to dashboard Cite

Chromatin immunoprecipitation identifies specific interactions between genomic DNA and proteins, advancing our understanding of gene-level and chromosome-level regulation. Based on chromatin immunoprecipitation experiments using validated antibodies, we define the genome-wide distributions of 19 histone modifications, one histone variant, and eight chromatin-associated proteins in Caenorhabditis elegans embryos and L3 larvae. Cluster analysis identified five groups of chromatin marks with shared features: Two groups correlate with gene repression, two with gene activation, and one with the X chromosome. The X chromosome displays numerous unique properties, including enrichment of monomethylated H4K20 and H3K27, which correlate with the different repressive mechanisms that operate in somatic tissues and germ cells, respectively. The data also revealed striking differences in chromatin composition between the autosomes and between chromosome arms and centers. Chromosomes I and III are globally enriched for marks of active genes, consistent with containing more highly expressed genes, compared to chromosomes II, IV, and especially V. Consistent with the absence of cytological heterochromatin and the holocentric nature of C. elegans chromosomes, markers of heterochromatin such as H3K9 methylation are not concentrated at a single region on each chromosome. Instead, H3K9 methylation is enriched on chromosome arms, coincident with zones of elevated meiotic recombination. Active genes in chromosome arms and centers have very similar histone mark distributions, suggesting that active domains in the arms are interspersed with heterochromatin-like structure. These data, which confirm and extend previous studies, allow for in-depth analysis of the organization and deployment of the C. elegans genome during development.

show abstract

“…A number of selected amino acid residues are subject to a variety of enzyme-catalyzed posttranslational modifications. These modifications include acetylation and methylation of lysines (K) and arginines (R), phosphorylation of serines (S) and threonines (T) [4,5] , which are carried out by a variety of chromatin modifying complexes, such as the COMPASS (for histone methylation), NuA4/ Tip60 (for Histone H4 acetylation), and NuA3 (for Histone H3 acetylation) complexes. All of these chromatin modifying complexes contain one of the histone modification enzymes, such as histone acetyltransferase (HAT), histone deacetylase (HDAC), histone methyltransferase (HMT), histone demethylase (HDMT), and histone kinase.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Hox epigenetic code

Ezziane¹

2012

WJCO

View full text Add to dashboard Cite

Archetypes of histone modifications associated with diverse chromosomal states that regulate access to DNA are leading the hypothesis of the histone code (or epigenetic code). However, it is still not evident how these post-translational modifications of histone tails lead to changes in chromatin structure. Histone modifications are able to activate and/or inactivate several genes and can be transmitted to next generation cells due to an epigenetic memory. The challenging issue is to identify or "decrypt" the code used to transmit these modifications to descent cells. Here, an attempt is made to describe how histone modifications operate as part of histone code that stipulates patterns of gene expression. This papers emphasizes particularly on the correlation between histone modifications and patterns of Hox gene expression in Caenorhabditis elegans . This work serves as an example to illustrate the power of the epigenetic machinery and its use in drug design and discovery.

show abstract

Germline chromatin

Cited by 73 publications

References 27 publications

Crossover Distribution and Frequency Are Regulated by him-5 in Caenorhabditis elegans

Crossover Distribution and Frequency Are Regulated by him-5 in Caenorhabditis elegans

Broad chromosomal domains of histone modification patterns in C. elegans

Analysis of the Hox epigenetic code

Contact Info

Product

Resources

About