title: roughex down-regulates G2 cyclins in G1.
abstract: Cell cycle arrest in G1 at the onset of patterning in the Drosophila eye is mediated by roughex. In roughex mutants, cells accumulate Cyclin A protein in early G1 and progress into S phase precociously. When Roughex is overexpressed in S/G2 cells, Cyclin A is mislocalized to the nucleus and degraded, preventing mitosis. Whereas Roughex inhibits Cyclin A accumulation, Cyclin E down-regulates Roughex protein in vivo. Roughex binds to Cyclin E and is a substrate for a Cyclin E-Cdk complex in vitro. These data argue that Roughex inhibits Cyclin A accumulation in early G1 by targeting Cyclin A for destruction. In late G1, Roughex is destabilized in a Cyclin E-dependent process, releasing Cyclin A for its role in S/G2.
authors.affiliation: Laboratory of Biochemistry, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA. bthomas@sunspot.nci.nih.gov
authors.forename: B J
authors.initials: BJ
authors.lastname: Thomas
authors.forename: K H
authors.initials: KH
authors.lastname: Zavitz
authors.forename: X
authors.initials: X
authors.lastname: Dong
authors.forename: M E
authors.initials: ME
authors.lastname: Lane
authors.forename: K
authors.initials: K
authors.lastname: Weigmann
authors.forename: R L
authors.initials: RL
authors.lastname: Finley
authors.forename: R
authors.initials: R
authors.lastname: Brent
authors.forename: C F
authors.initials: CF
authors.lastname: Lehner
authors.forename: S L
authors.initials: SL
authors.lastname: Zipursky
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000235:genetics*; D015536:Down-Regulation; D004330:Drosophila / Q000166:cytology / Q000235:genetics; D029721:Drosophila Proteins; D005123:Eye / Q000166:cytology / Q000378:metabolism; D005136:Eye Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D005136:Eye Proteins; C088084:rux protein, Drosophila