title: Targeting of Painting of fourth to roX1 and roX2 proximal sites suggests evolutionary links between dosage compensation and the regulation of the fourth chromosome in Drosophila melanogaster.
abstract: In Drosophila melanogaster, two chromosome-specific targeting and regulatory systems have been described. The male-specific lethal (MSL) complex supports dosage compensation by stimulating gene expression from the male X-chromosome, and the protein Painting of fourth (POF) specifically targets and stimulates expression from the heterochromatic 4(th) chromosome. The targeting sites of both systems are well characterized, but the principles underlying the targeting mechanisms have remained elusive. Here we present an original observation, namely that POF specifically targets two loci on the X-chromosome, PoX1 and PoX2 (POF-on-X). PoX1 and PoX2 are located close to the roX1 and roX2 genes, which encode noncoding RNAs important for the correct targeting and spreading of the MSL-complex. We also found that the targeting of POF to PoX1 and PoX2 is largely dependent on roX expression and identified a high-affinity target region that ectopically recruits POF. The results presented support a model linking the MSL-complex to POF and dosage compensation to regulation of heterochromatin.
authors.affiliation: Department of Molecular Biology, Umeå University, SE-90187 Umeå, Sweden.
authors.forename: Lina E
authors.initials: LE
authors.lastname: Lundberg
authors.forename: Maria
authors.initials: M
authors.lastname: Kim
authors.forename: Anna-Mia
authors.initials: AM
authors.lastname: Johansson
authors.forename: Marie-Line
authors.initials: ML
authors.lastname: Faucillion
authors.forename: Rafael
authors.initials: R
authors.lastname: Josupeit
authors.forename: Jan
authors.initials: J
authors.lastname: Larsson
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D005075:Biological Evolution; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics*; D002875:Chromosomes / Q000235:genetics*; D004303:Dosage Compensation, Genetic; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D015870:Gene Expression; D056426:Genetic Loci; D006570:Heterochromatin / Q000235:genetics / Q000378:metabolism; D008297:Male; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D014960:X Chromosome
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D006570:Heterochromatin; D009687:Nuclear Proteins; C092595:Pabp2 protein, Drosophila; C430458:Pof protein, Drosophila; D022661:RNA, Untranslated; D016601:RNA-Binding Proteins; D014157:Transcription Factors; C082132:msl-1 protein, Drosophila; C454144:roX1 protein, Drosophila
keywords: Drosophila melanogaster; Painting of fourth; dosage compensation; epigenetics; heterochromatin