Repression of RNA polymerase II transcription by a Drosophila oligopeptide.
BACKGROUND
Germline progenitors resist signals that promote differentiation into somatic cells. This occurs through the transient repression in primordial germ cells of RNA polymerase II, specifically by disrupting Ser2 phosphorylation on its C-terminal domain.


RESULTS
Here we show that contrary to expectation the Drosophila polar granule component (pgc) gene functions as a protein rather than a non-coding RNA. Surprisingly, pgc encodes a 71-residue, dimeric, alpha-helical oligopeptide repressor. In vivo data show that Pgc ablates Ser2 phosphorylation of the RNA polymerase II C-terminal domain and completely suppresses early zygotic transcription in the soma.


CONCLUSIONS
We thus identify pgc as a novel oligopeptide that readily inhibits gene expression. Germ cell repression of transcription in Drosophila is thus catalyzed by a small inhibitor protein.
Gene Expression Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
Gyula
G
Timinszky
Miriam
M
Bortfeld
Andreas G
AG
Ladurner
D000818:Animals; D003001:Cloning, Molecular; D004330:Drosophila / Q000196:embryology / Q000235:genetics*; D017403:In Situ Hybridization; D009842:Oligopeptides / Q000502:physiology*; D016366:Open Reading Frames; D010766:Phosphorylation; D012319:RNA Polymerase II / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
D009842:Oligopeptides; D012333:RNA, Messenger; D012319:RNA Polymerase II