Nuclear membrane protein LAP2β mediates transcriptional repression alone and together with its binding partner GCL (germ-cell-less)

E. Nili, G. S. Cojocaru, Y. Kalma, D. Ginsberg, Neal G. Copeland, D. J. Gilbert, Nancy A. Jenkins, R. Berger, S. Shaklai, N. Amariglio, F. Brok-Simoni, A. J. Simon, G. Rechavi

Research output: Contribution to journalArticle

163 Scopus citations

Abstract

LAP2β is an integral membrane protein of the nuclear envelope involved in chromatin and nuclear architecture. Using the yeast two-hybrid system, we have cloned a novel LAP2β-binding protein, mGCL, which contains a BTB/POZ domain and is the mouse homologue of the Drosophila germ-cell-less (GCL) protein. In Drosophila embryos, GCL was shown to be essential for germ cell formation and was localized to the nuclear envelope. Here, we show that, in mammalian cells, GCL is co-localized with LAP2β to the nuclear envelope. Nuclear fractionation studies reveal that mGCL acts as a nuclear matrix component and not as an integral protein of the nuclear envelope. Recently, mGCL was found to interact with the DP3α component of the E2F transcription factor. This interaction reduced the transcriptional activity of the E2F-DP heterodimer, probably by anchoring the complex to the nuclear envelope. We demonstrate here that LAP2β is also capable of reducing the transcriptional activity of the E2F-DP complex and that it is more potent than mGCL in doing so. Co-expression of both LAP2β and mGCL with the E2F-DP complex resulted in a reduced transcriptional activity equal to that exerted by the pRb protein.

Original languageEnglish (US)
Pages (from-to)3297-3307
Number of pages11
JournalJournal of Cell Science
Volume114
Issue number18
StatePublished - Nov 7 2001

Keywords

  • GCL
  • Germ-cell-less
  • LAP2
  • Nuclear envelope
  • Thymopoietin
  • Transcription regulation

ASJC Scopus subject areas

  • Cell Biology

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