title: Synthesis of polyphosphoinositides in nuclei of Friend cells. Evidence for polyphosphoinositide metabolism inside the nucleus which changes with cell differentiation.
abstract: Previous work demonstrated the existence of phosphatidylinositol kinase and phosphatidylinositol phosphate kinase in rat liver nuclei, with the suggestion that these activities are in the nuclear membrane [Smith & Wells (1983) J. Biol. Chem. 258, 9368-9373]. Here we show that highly purified nuclei from Friend cells, washed free of nuclear membrane by Triton, can incorporate radiolabel from [gamma-32P]ATP into phosphatidic acid, phosphatidylinositol phosphate and phosphatidylinositol 4,5-bisphosphate. The degree of radiolabelling of phosphatidylinositol bisphosphate is highly dependent on the state of differentiation of the cells, being barely detectable in growing cells and much greater after dimethyl sulphoxide-induced differentiation; this difference is mostly due to different amounts of phosphatidylinositol phosphate in the isolated nuclei. We suggest that polyphosphoinositides are made inside the nucleus and that they have a role in chromatin function; either the phospholipids themselves play a role, or there is a possibility of intranuclear signalling by inositide-derived molecules.
authors.affiliation: Istituto di Anatomia Umana Normale, University of Bologna, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Cocco
authors.forename: R S
authors.initials: RS
authors.lastname: Gilmour
authors.forename: A
authors.initials: A
authors.lastname: Ognibene
authors.forename: A J
authors.initials: AJ
authors.lastname: Letcher
authors.forename: F A
authors.initials: FA
authors.lastname: Manzoli
authors.forename: R F
authors.initials: RF
authors.lastname: Irvine
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D002855:Chromatography, Thin Layer; D005622:Friend murine leukemia virus; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism* / Q000648:ultrastructure; D007942:Leukemia, Experimental / Q000378:metabolism*; D008055:Lipids / Q000096:biosynthesis; D051379:Mice; D008854:Microscopy, Electron; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000096:biosynthesis*
chemical_list: D008055:Lipids; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols