title: A novel predicted bromodomain-related protein affects coordination between meiosis and spermiogenesis in Drosophila and is required for male meiotic cytokinesis.
abstract: Temporal coordination of meiosis with spermatid morphogenesis is crucial for successful generation of mature sperm cells. We identified a recessive male sterile Drosophila melanogaster mutant, mitoshell, in which events of spermatid morphogenesis are initiated too early, before meiotic onset. Premature mitochondrial aggregation and fusion lead to an aberrant mitochondrial shell around premeiotic nuclei. Despite successful meiotic karyokinesis, improper mitochondrial localization in mitoshell testes is associated with defective astral central spindles and a lack of contractile rings, leading to meiotic cytokinesis failure. We mapped and cloned the mitoshell gene and found that it encodes a novel protein with a bromodomain-related region. It is conserved in some insect lineages. Bromodomains typically bind to histone acetyl-lysine residues and therefore are often associated with chromatin. The Mitoshell bromodomain-related region is predicted to have an alpha helical structure similar to that of bromodomains, but not all the crucial residues in the ligand-binding loops are conserved. We speculate that Mitoshell may participate in transcriptional regulation of spermatogenesis-specific genes, though perhaps with different ligand specificity compared to traditional bromodomains.
authors.affiliation: Department of Biology, Davidson College , Davidson, NC 28035, USA.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Bergner
authors.forename: F Edward
authors.initials: FE
authors.lastname: Hickman
authors.forename: Kathleen H
authors.initials: KH
authors.lastname: Wood
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Wakeman
authors.forename: Hunter H
authors.initials: HH
authors.lastname: Stone
authors.forename: Tessa J
authors.initials: TJ
authors.lastname: Campbell
authors.forename: Samantha B
authors.initials: SB
authors.lastname: Lightcap
authors.forename: Sheena M
authors.initials: SM
authors.lastname: Favors
authors.forename: Amanda C
authors.initials: AC
authors.lastname: Aldridge
authors.forename: Karen G
authors.initials: KG
authors.lastname: Hales
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002868:Chromosomal Proteins, Non-Histone / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D048749:Cytokinesis / Q000235:genetics; D029721:Drosophila Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005260:Female; D017344:Genes, Insect / Q000235:genetics; D007248:Infertility, Male / Q000235:genetics; D019476:Insect Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008540:Meiosis / Q000235:genetics; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D017434:Protein Structure, Tertiary; D013091:Spermatogenesis / Q000235:genetics; D013737:Testis / Q000254:growth & development / Q000378:metabolism
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D029721:Drosophila Proteins; D019476:Insect Proteins; C552421:mtsh protein, Drosophila