A maternal factor unique to ascidians silences the germline via binding to P-TEFb and RNAP II regulation

Gaku Kumano, Naohito Takatori, Takefumi Negishi, Tatsuki Takada, Hiroki Nishida

研究成果: Article査読

41 被引用数 (Scopus)


Suppression of zygotic transcription in early embryonic germline cells is tightly linked to their separation from the somatic lineage. Many invertebrate embryos utilize localized maternal factors that are successively inherited by the germline cells for silencing the germline. Germline quiescence has also been associated with the underphosphorylation of Ser2 of the C-terminal domain (CTD-Ser2) of RNA polymerase II [1-3]. Here, using the ascidian Halocynthia roretzi, we identified a first deuterostome example of a maternally localized factor, posterior end mark (PEM), which globally represses germline transcription. PEM knockdown resulted in ectopic transcription and ectopic phosphorylation of CTD-Ser2 in the germline. Overexpression of PEM abolished all transcription and led to the underphosphorylation of CTD-Ser2 in the somatic cells. PEM protein was reiteratively detected in the nucleus of the germline cells and coimmunoprecipitated with CDK9, a component of posterior transcription elongation factor b (P-TEFb). These results suggest that nonhomologous proteins, PEM and Pgc of Drosophila [3-5] and PIE-1 of C. elegans [1, 6, 7], repress germline gene expression through analogous functions: by keeping CTD-Ser2 underphosphorylated through binding to the P-TEFb complex. The present study is an interesting example of evolutionary constraint on how a mechanism of germline silencing can evolve in diverse animals.

ジャーナルCurrent Biology
出版ステータスPublished - 2011 8 9

ASJC Scopus subject areas

  • 生化学、遺伝学、分子生物学(全般)
  • 農業および生物科学(全般)


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