Butyrate sensitive suppressor of position-effect variegation mutations in drosophila melanogaster

Abstract

Mutations at a locus on chromosome II of D. melanogaster suppressing position-effect variegation mutations have been identified which display recessive butyrate sensitivity. Survival of homozygous mutant flies is significantly reduced on medium containing sodium n-butyrate. The butyrate sensitive suppressor mutations are further characterized by recessive female sterility and reduced survival of homozygotes. Complementation analysis showed their allelism. The locus of these mutations, Su-var (2) 1, has been localized to 40.5 +/- 0.2 and, by using interstitial duplications, to region 31CD on the cytogenetic map. Moreover, the mutant alleles of the Su-var (2) 1 locus display a lethal interaction with the heterochromatic Y chromosome. The presence or absence of a Y chromosome in males or females has a strong influence on the viability of homozygous or transheterozygous suppressor flies. All the genetic properties of Su-var (2) 1 mutants suggest strongly that this locus affects chromosome condensation.

Chromatin Proteins Are Determinants of Centromere Function

“…A mutation in a histone deacetylase was observed to decrease H3 Lys 9 methylation at centric heterochromatin in chromatin immunoprecipitation experiments, indicating that acetyl groups on histone tails inhibit Su(var) 3-9 activity (Nakayama et al 2001). Consistent with these data, the treatment of cells with drugs that inhibit histone deacetylases has long been known to inhibit centromeric silencing in S. pombe and Drosophila (Ekwall et al 1997;Reuter et al 1982). Further, evidence for a biochemical interaction between Drosophila Su(var)3-9 and HDAC1 indicates that histone deacetylases could act in a direct manner to recruit Su(var)3-9 (Czermin et al 2001).…”

Drosophila longevity is not affected by heterochromatin‐mediated gene silencing

“…Approximately 150 loci in Drosophila can either increase or decrease heterochromatin silencing when mutated (Schotta et al ., 2003). With the same genetic design described for the mutants of HP1, we assessed the survivorship and mortality rate of adults heterozygous for E2F and Su(var)2-1 mutations which increase or decrease heterochromatin silencing, respectively (Reuter et al ., 1982;Dorn et al ., 1986;Seum et al ., 1996). The E2F 91 mutation creates a stop codon near the beginning of the E2F coding sequence (Duronio et al ., 1995).…”

P transposon-induced dominant enhancer mutations of position-effect variegation in Drosophila melanogaster

“…The translocations T(2;3)apxa + In(2L)Cy, apXaCy E-var(3)l'' and T(2;3)apxa, ap.xaSu-var(2)10' were used to screen for new1 induced dommant suppressors and enhancers of In(1)w" ' PEV. The dominant enhancer effect of E-var(3)1°' as well as the dominant suppressor effect of Su-var(2)1°' are very sensitive to the effect of other modifier mutations (Reuter and WOLFF 198 DORN and HOFFMANN 1982;REUTER, HOFFMANN and WOLFF 1983). Therefore, E-var(3)1°' was used to test for new suppressors, and Su-var(2)1°' was used to select newly induced enhancers.…”

“…Sequencing of these genes appears to confirm the hypothesis that such genes encode regulatory or structural components of chromatin. In addition, the mutations of another suppressor locus, Su-var(2)1, which were found to reduce H4 deacetylation and chromatin packaging ( , are butyrate sensitive and display a lethal interaction to extra Y heterochromatin (REUTER, DORN and HOFFMANN 1982). The mutations of two other suppressor loci show identical pleiotropic genetic effects .…”