title: Stem cell division is regulated by the microRNA pathway.
abstract: One of the key characteristics of stem cells is their capacity to divide for long periods of time in an environment where most of the cells are quiescent. Therefore, a critical question in stem cell biology is how stem cells escape cell division stop signals. Here, we report the necessity of the microRNA (miRNA) pathway for proper control of germline stem cell (GSC) division in Drosophila melanogaster. Analysis of GSCs mutant for dicer-1 (dcr-1), the double-stranded RNaseIII essential for miRNA biogenesis, revealed a marked reduction in the rate of germline cyst production. These dcr-1 mutant GSCs exhibit normal identity but are defective in cell cycle control. On the basis of cell cycle markers and genetic interactions, we conclude that dcr-1 mutant GSCs are delayed in the G1 to S transition, which is dependent on the cyclin-dependent kinase inhibitor Dacapo, suggesting that miRNAs are required for stem cells to bypass the normal G1/S checkpoint. Hence, the miRNA pathway might be part of a mechanism that makes stem cells insensitive to environmental signals that normally stop the cell cycle at the G1/S transition.
authors.affiliation: Department of Biochemistry, University of Washington, J591, HSB, Seattle, Washington 98195-7350, USA.
authors.forename: S D
authors.initials: SD
authors.lastname: Hatfield
authors.forename: H R
authors.initials: HR
authors.lastname: Shcherbata
authors.forename: K A
authors.initials: KA
authors.lastname: Fischer
authors.forename: K
authors.initials: K
authors.lastname: Nakahara
authors.forename: R W
authors.initials: RW
authors.lastname: Carthew
authors.forename: H
authors.initials: H
authors.lastname: Ruohola-Baker
mesh_terms: D000818:Animals; D002455:Cell Division; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology* / Q000201:enzymology / Q000235:genetics*; D016193:G1 Phase; D017353:Gene Deletion; D016678:Genome; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D043244:Ribonuclease III / Q000235:genetics / Q000378:metabolism; D016196:S Phase; D013234:Stem Cells / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; D035683:MicroRNAs; D009687:Nuclear Proteins; C103336:dap protein, Drosophila; D043244:Ribonuclease III