Global Transcriptional Repression in C. Elegans Germline Precursors by Regulated Sequestration of TAF-4

Cell. 2008 Oct 3;135(1):149-60. doi: 10.1016/j.cell.2008.07.040.

Abstract

In C. elegans, four asymmetric divisions, beginning with the zygote (P0), generate transcriptionally repressed germline blastomeres (P1-P4) and somatic sisters that become transcriptionally active. The protein PIE-1 represses transcription in the later germline blastomeres but not in the earlier germline blastomeres P0 and P1. We show here that OMA-1 and OMA-2, previously shown to regulate oocyte maturation, repress transcription in P0 and P1 by binding to and sequestering in the cytoplasm TAF-4, a component critical for assembly of TFIID and the pol II preinitiation complex. OMA-1/2 binding to TAF-4 is developmentally regulated, requiring phosphorylation by the DYRK kinase MBK-2, which is activated at meiosis II after fertilization. OMA-1/2 are normally degraded after the first mitosis, but ectopic expression of wild-type OMA-1 is sufficient to repress transcription in both somatic and later germline blastomeres. We propose that phosphorylation by MBK-2 serves as a developmental switch, converting OMA-1/2 from oocyte to embryo regulators.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Blastomeres / metabolism*
  • Caenorhabditis elegans / embryology*
  • Caenorhabditis elegans / genetics*
  • Caenorhabditis elegans / metabolism
  • Caenorhabditis elegans Proteins / chemistry
  • Caenorhabditis elegans Proteins / metabolism*
  • Carrier Proteins / metabolism
  • Gene Expression Regulation, Developmental
  • Histones / metabolism
  • Molecular Sequence Data
  • Oocytes / metabolism
  • Phosphorylation
  • Protein Structure, Tertiary
  • Protein-Tyrosine Kinases / metabolism
  • Repressor Proteins / chemistry
  • Repressor Proteins / metabolism
  • Transcription Factors / chemistry
  • Transcription Factors / metabolism*
  • Zygote / cytology
  • Zygote / metabolism*

Substances

  • Caenorhabditis elegans Proteins
  • Carrier Proteins
  • Histones
  • OMA-1 protein, C elegans
  • Repressor Proteins
  • TAF-12 protein, C elegans
  • TAF-4 protein, C elegans
  • Transcription Factors
  • oma-2 protein, C elegans
  • MBK-2 protein, C elegans
  • Protein-Tyrosine Kinases