title: Mei-P26 regulates the maintenance of ovarian germline stem cells by promoting BMP signaling.
abstract: In the Drosophila ovary, bone morphogenetic protein (BMP) ligands maintain germline stem cells (GSCs) in an undifferentiated state. The activation of the BMP pathway within GSCs results in the transcriptional repression of the differentiation factor bag of marbles (bam). The Nanos-Pumilio translational repressor complex and the miRNA pathway also help to promote GSC self-renewal. How the activities of different transcriptional and translational regulators are coordinated to keep the GSC in an undifferentiated state remains uncertain. Data presented here show that Mei-P26 cell-autonomously regulates GSC maintenance in addition to its previously described role of promoting germline cyst development. Within undifferentiated germ cells, Mei-P26 associates with miRNA pathway components and represses the translation of a shared target mRNA, suggesting that Mei-P26 can enhance miRNA-mediated silencing in specific contexts. In addition, disruption of mei-P26 compromises BMP signaling, resulting in the inappropriate expression of bam in germ cells immediately adjacent to the cap cell niche. Loss of mei-P26 results in premature translation of the BMP antagonist Brat in germline stem cells. These data suggest that Mei-P26 has distinct functions in the ovary and participates in regulating the fates of both GSCs and their differentiating daughters.
authors.affiliation: Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390-9148, USA.
authors.forename: Yun
authors.initials: Y
authors.lastname: Li
authors.forename: Jean Z
authors.initials: JZ
authors.lastname: Maines
authors.forename: Omür Y
authors.initials: OY
authors.lastname: Tastan
authors.forename: Dennis M
authors.initials: DM
authors.lastname: McKearin
authors.forename: Michael
authors.initials: M
authors.lastname: Buszczak
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D005854:Germ Cells / Q000166:cytology* / Q000378:metabolism; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D035683:MicroRNAs / Q000378:metabolism; D010053:Ovary / Q000166:cytology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism
chemical_list: D019485:Bone Morphogenetic Proteins; D029721:Drosophila Proteins; C530643:Mei-P26 protein, Drosophila; D035683:MicroRNAs; C091674:bam protein, Drosophila