title: The epigenetic H3S10 phosphorylation mark is required for counteracting heterochromatic spreading and gene silencing in Drosophila melanogaster.
abstract: The JIL-1 kinase localizes specifically to euchromatin interband regions of polytene chromosomes and is the kinase responsible for histone H3S10 phosphorylation at interphase. Genetic interaction assays with strong JIL-1 hypomorphic loss-of-function alleles have demonstrated that the JIL-1 protein can counterbalance the effect of the major heterochromatin components on position-effect variegation (PEV) and gene silencing. However, it is unclear whether this was a causative effect of the epigenetic H3S10 phosphorylation mark, or whether the effect of the JIL-1 protein on PEV was in fact caused by other functions or structural features of the protein. By transgenically expressing various truncated versions of JIL-1, with or without kinase activity, and assessing their effect on PEV and heterochromatic spreading, we show that the gross perturbation of polytene chromosome morphology observed in JIL-1 null mutants is unrelated to gene silencing in PEV and is likely to occur as a result of faulty polytene chromosome alignment and/or organization, separate from epigenetic regulation of chromatin structure. Furthermore, the findings provide evidence that the epigenetic H3S10 phosphorylation mark itself is necessary for preventing the observed heterochromatic spreading independently of any structural contributions from the JIL-1 protein.
authors.affiliation: Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University Ames, IA 50011,  USA.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.forename: Weili
authors.initials: W
authors.lastname: Cai
authors.forename: Yeran
authors.initials: Y
authors.lastname: Li
authors.forename: Huai
authors.initials: H
authors.lastname: Deng
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Bao
authors.forename: Jack
authors.initials: J
authors.lastname: Girton
authors.forename: Jørgen
authors.initials: J
authors.lastname: Johansen
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Johansen
mesh_terms: D000818:Animals; D055012:Chromosomal Position Effects; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000235:genetics* / Q000378:metabolism; D044127:Epigenesis, Genetic; D005123:Eye / Q000033:anatomy & histology; D020868:Gene Silencing; D006570:Heterochromatin / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D019076:Transgenes
chemical_list: D029721:Drosophila Proteins; D006570:Heterochromatin; D006657:Histones; C507306:JIL-1 protein, Drosophila; D017346:Protein Serine-Threonine Kinases