Central role of Drosophila SU(VAR)3–9 in histone H3-K9 methylation and heterochromatic gene silencing
AUTOR(ES)
Schotta, Gunnar
FONTE
Oxford University Press
RESUMO
Su(var)3–9 is a dominant modifier of heterochromatin-induced gene silencing. Like its mammalian and Schizosaccharomyces pombe homologues, Su(var) 3–9 encodes a histone methyltransferase (HMTase), which selectively methylates histone H3 at lysine 9 (H3-K9). In Su(var)3–9 null mutants, H3-K9 methylation at chromocentre heterochromatin is strongly reduced, indicating that SU(VAR)3–9 is the major heterochromatin-specific HMTase in Drosophila. SU (VAR)3–9 interacts with the heterochromatin-associated HP1 protein and with another silencing factor, SU(VAR)3–7. Notably, SU(VAR)3–9–HP1 interaction is interdependent and governs distinct localization patterns of both proteins. In Su(var)3–9 null mutants, concentration of HP1 at the chromocentre is nearly lost without affecting HP1 accumulation at the fourth chromosome. By contrast, in HP1 null mutants SU(VAR)3–9 is no longer restricted at heterochromatin but broadly dispersed across the chromosomes. Despite this interdependence, Su(var)3–9 dominates the PEV modifier effects of HP1 and Su(var)3–7 and is also epistatic to the Y chromosome effect on PEV. Finally, the human SUV39H1 gene is able to partially rescue Su(var)3–9 silencing defects. Together, these data indicate a central role for the SU(VAR)3–9 HMTase in heterochromatin-induced gene silencing in Drosophila.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=125909Documentos Relacionados
- Physical and functional association of SU(VAR)3-9 and HDAC1 in Drosophila
- Set Domain-Dependent Regulation of Transcriptional Silencing and Growth Control by SUV39H1, a Mammalian Ortholog of Drosophila Su(var)3-9
- The protein encoded by the Drosophila position-effect variegation suppressor gene Su(var)3-9 combines domains of antagonistic regulators of homeotic gene complexes.
- Distinct HP1 and Su(var)3-9 complexes bind to sets of developmentally coexpressed genes depending on chromosomal location
- Selective Interactions between Vertebrate Polycomb Homologs and the SUV39H1 Histone Lysine Methyltransferase Suggest that Histone H3-K9 Methylation Contributes to Chromosomal Targeting of Polycomb Group Proteins