Encore facilitates SCF-Ubiquitin-proteasome-dependent proteolysis during Drosophila oogenesis.
Exit from the cell cycle requires the downregulation of Cyclin/Cdk activity. In the ovary of Drosophila, Encore activity is necessary in the germline to exit the division program after four mitotic divisions. We find that in encore mutant germaria, Cyclin A persists longer than in wild type. In addition, Cyclin E expression is not downregulated after the fourth mitosis and accumulates in a polyubiquitinated form. Mutations in genes coding for components of the SCF pathway such as cul1, UbcD2 and effete enhance the extra division phenotype of encore. We show that Encore physically interacts with the proteasome, Cul1 and Cyclin E. The association of Cul1, phosphorylated Cyclin E and the proteasome 19S-RP subunit S1 with the fusome is affected in encore mutant germaria. We propose that in encore mutant germaria the proteolysis machinery is less efficient and, in addition, reduced association of Cul1 and S1 with the fusome may compromise Cyclin E destruction and consequently promote an extra round of mitosis.
Ohlmeyer
Johanna Talavera
JT
HHMI/Molecular Biology Department, Princeton University, Princeton, NJ 08544, USA.
Schüpbach
Trudi
T
D000818:Animals; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins / Q000235:genetics*; D002455:Cell Division / Q000235:genetics; D019925:Cyclin A / Q000172:deficiency / Q000235:genetics; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004278:DNA, Superhelical / Q000235:genetics; D004330:Drosophila / Q000196:embryology* / Q000235:genetics*; D029721:Drosophila Proteins; D005020:Ethyl Methanesulfonate; D005136:Eye Proteins / Q000235:genetics; D005260:Female; D017353:Gene Deletion; D009097:Multienzyme Complexes / Q000378:metabolism*; D016296:Mutagenesis; D009153:Mutagens; D009154:Mutation; D009687:Nuclear Proteins; D009866:Oogenesis / Q000502:physiology*; D010053:Ovary / Q000502:physiology; D010641:Phenotype; D046988:Proteasome Endopeptidase Complex; D025801:Ubiquitin / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D019925:Cyclin A; C115373:DNA supercoiling factor, Drosophila; D004278:DNA, Superhelical; D029721:Drosophila Proteins; D005136:Eye Proteins; D009097:Multienzyme Complexes; D009153:Mutagens; D009687:Nuclear Proteins; D025801:Ubiquitin; C088084:rux protein, Drosophila; D005020:Ethyl Methanesulfonate; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex