title: Maintaining sufficient nanos is a critical function for polar granule component in the specification of primordial germ cells.
abstract: Primordial germ cells (PGC) are the precursors of germline stem cells. In Drosophila, PGC specification is thought to require transcriptional quiescence and three genes, polar granule component (pgc), nanos (nos), and germ cell less (gcl) function to downregulate Pol II transcription. While it is not understood how nos or gcl represses transcription, pgc does so by inhibiting the transcription elongation factor b (P-TEFb), which is responsible for phosphorylating Ser2 residues in the heptad repeat of the C-terminal domain (CTD) of the largest Pol II subunit. In the studies reported here, we demonstrate that nos are a critical regulatory target of pgc. We show that a substantial fraction of the PGCs in pgc embryos have greatly reduced levels of Nos protein and exhibit phenotypes characteristic of nos PGCs. Lastly, restoring germ cell-specific expression of Nos is sufficient to ameliorate the pgc phenotype.
authors.affiliation: Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
authors.forename: Girish
authors.initials: G
authors.lastname: Deshpande
authors.forename: Emma
authors.initials: E
authors.lastname: Spady
authors.forename: Joe
authors.initials: J
authors.lastname: Goodhouse
authors.forename: Paul
authors.initials: P
authors.lastname: Schedl
mesh_terms: D000818:Animals; D004330:Drosophila / Q000196:embryology / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D042925:Positive Transcriptional Elongation Factor B / Q000235:genetics* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D029721:Drosophila Proteins; D036341:Intercellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; C076187:gcl protein, Drosophila; C527201:pgc protein, Drosophila; C070574:nos protein, Drosophila; D042925:Positive Transcriptional Elongation Factor B