Search results for "Centric heterochromatin"
showing 4 items of 4 documents
Adaptation of gene loci to heterochromatin in the course of Drosophila evolution is associated with insulator proteins.
2020
AbstractPericentromeric heterochromatin is generally composed of repetitive DNA forming a transcriptionally repressive environment. Dozens of genes were embedded into pericentromeric heterochromatin during evolution of Drosophilidae lineage while retaining activity. However, factors that contribute to insusceptibility of gene loci to transcriptional silencing remain unknown. Here, we find that the promoter region of genes that can be embedded in both euchromatin and heterochromatin exhibits a conserved structure throughout the Drosophila phylogeny and carries motifs for binding of certain chromatin remodeling factors, including insulator proteins. Using ChIP-seq data, we demonstrate that ev…
Insulator proteins contribute to expression of gene loci repositioned into heterochromatin in the course ofDrosophilaevolution
2019
AbstractPericentric heterochromatin inDrosophilais generally composed of repetitive DNA forming a transcriptionally repressive environment. Nevertheless, dozens of genes were embedded into pericentric genome regions during evolution ofDrosophilidaelineage and retained functional activity. However, factors that contribute to “immunity” of these gene loci to transcriptional silencing remain unknown. Here, we investigated molecular evolution of the essentialMybandRanbp16genes. These protein-coding genes reside in euchromatic loci of chromosome X inD. melanogasterand related species, while in other studiedDrosophilaspecies, including evolutionary distant ones, they are located in genomic region…
Linker histone H1 is essential for Drosophila development, the establishment of pericentric heterochromatin, and a normal polytene chromosome structu…
2009
We generated mutant alleles of Drosophila melanogaster in which expression of the linker histone H1 can be down-regulated over a wide range by RNAi. When the H1 protein level is reduced to ∼20% of the level in wild-type larvae, lethality occurs in the late larval – pupal stages of development. Here we show that H1 has an important function in gene regulation within or near heterochromatin. It is a strong dominant suppressor of position effect variegation (PEV). Similar to other suppressors of PEV, H1 is simultaneously involved in both the repression of euchromatic genes brought to the vicinity of pericentric heterochromatin and the activation of heterochromatic genes that depend on their pe…
Drosophila Enhancer of Zeste/ESC Complexes Have a Histone H3 Methyltransferase Activity that Marks Chromosomal Polycomb Sites
2002
AbstractEnhancer of Zeste is a Polycomb Group protein essential for the establishment and maintenance of repression of homeotic and other genes. In the early embryo it is found in a complex that includes ESC and is recruited to Polycomb Response Elements. We show that this complex contains a methyltransferase activity that methylates lysine 9 and lysine 27 of histone H3, but the activity is lost when the E(Z) SET domain is mutated. The lysine 9 position is trimethylated and this mark is closely associated with Polycomb binding sites on polytene chromosomes but is also found in centric heterochromatin, chromosome 4, and telomeric sites. Histone H3 methylated in vitro by the E(Z)/ESC complex …