Reduced levels of Su(var)3-9 but not Su(var)2-5 (HP1) counteract the effects on chromatin structure and viability in loss-of-function mutants of the JIL-1 histone H3S10 kinase.
It has recently been demonstrated that activity of the essential JIL-1 histone H3S10 kinase is a major regulator of chromatin structure and that it functions to maintain euchromatic domains while counteracting heterochromatization and gene silencing. In the absence of JIL-1 kinase activity, the major heterochromatin markers histone H3K9me2 and HP1 spread in tandem to ectopic locations on the chromosome arms. In this study, we show that the lethality as well as some of the chromosome morphology defects associated with the null JIL-1 phenotype to a large degree can be rescued by reducing the dose of the Su(var)3-9 gene. This effect was observed with three different alleles of Su(var)3-9, strongly suggesting it is specific to Su(var)3-9 and not to second site modifiers. This is in contrast to similar experiments performed with alleles of the Su(var)2-5 gene that codes for HP1 in Drosophila where no genetic interactions were detectable between JIL-1 and Su(var)2-5. Taken together, these findings indicate that while Su(var)3-9 histone methyltransferase activity is a major factor in the lethality and chromatin structure perturbations associated with loss of the JIL-1 histone H3S10 kinase, these effects are likely to be uncoupled from HP1.
Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA. kristen@iastate.edu
Huai
H
Deng
Xiaomin
X
Bao
Weiguo
W
Zhang
Jack
J
Girton
Jørgen
J
Johansen
Kristen M
KM
Johansen
D000818:Animals; D030801:Animals, Genetically Modified; D002470:Cell Survival; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics* / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D020868:Gene Silencing; D006570:Heterochromatin / Q000737:chemistry* / Q000235:genetics; D006657:Histones / Q000378:metabolism; D019656:Loss of Heterozygosity / Q000235:genetics*; D010641:Phenotype; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism
D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D006570:Heterochromatin; D006657:Histones; D012097:Repressor Proteins; C089148:Su(var)3-9 protein, Drosophila; C452193:heterochromatin protein 1, Drosophila; C507306:JIL-1 protein, Drosophila; D017346:Protein Serine-Threonine Kinases