title: Drosophila PLUTONIUM protein is a specialized cell cycle regulator required at the onset of embryogenesis.
abstract: Unfertilized eggs and fertilized embryos from Drosophila mothers mutant for the plutonium (plu) gene contain giant polyploid nuclei resulting from unregulated S-phase. The PLU protein, a 19-kDa ankyrin repeat protein, is present in oocytes and early embryos but is not detectable after the completion of the initial rapid S-M cycles of the embryo. The persistence of the protein during the early embryonic divisions is consistent with a direct role in linking S-phase and M-phase. When ectopically expressed in the eye disc, PLU did not perturb the cell cycle, suggesting that PLU regulates S-phase only in early embryonic development. The pan gu (png) and giant nuclei (gnu) genes also affect the S-phase in the unfertilized egg and early embryo. We show that functional png is needed for the presence of PLU protein. By analyzing png mutations of differing severity, we find that the extent of the png mutant phenotype inversely reflects the level of PLU protein. Our data suggest that PLU protein is required at the time of egg activation and the completion of meiosis.
authors.affiliation: Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, USA.
authors.forename: L K
authors.initials: LK
authors.lastname: Elfring
authors.forename: J M
authors.initials: JM
authors.lastname: Axton
authors.forename: D D
authors.initials: DD
authors.lastname: Fenger
authors.forename: A W
authors.initials: AW
authors.lastname: Page
authors.forename: J L
authors.initials: JL
authors.lastname: Carminati
authors.forename: T L
authors.initials: TL
authors.lastname: Orr-Weaver
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000235:genetics*; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000502:physiology*; D005123:Eye / Q000196:embryology; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D019476:Insect Proteins / Q000235:genetics / Q000502:physiology*; D008297:Male; D008540:Meiosis; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009799:Ocular Physiological Phenomena; D010063:Ovum / Q000378:metabolism; D054645:Protein Phosphatase 1; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005136:Eye Proteins; D019476:Insect Proteins; D009419:Nerve Tissue Proteins; C085874:PLU protein, Drosophila; C099933:Ppp1r14b protein, mouse; D011506:Proteins; D014157:Transcription Factors; C075638:aos protein, Drosophila; D054645:Protein Phosphatase 1