Microspherule protein 1, Mi-2β, and RET finger protein associate in the nucleolus and up-regulate ribosomal gene transcription

Keiko Shimono, Yohei Shimono, Kaoru Shimokata, Naoki Ishiguro, Masahide Takahashi

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

The nucleolus is the site of ribosomal DNA (rDNA) transcription and ribosome production. In exploring the role of nucleolar protein MCRS1 (microspherule protein1)/MSP58 (58-kDa microspherule protein), we found that Mi-2β, a component of a nucleosome remodeling and deacetylase (NuRD) complex, RET finger protein (RFP), and upstream binding factor (UBF) were associated with MCRS1. Yeast two-hybrid assays revealed that MCRS1 bound to the ATPase/helicase region of Mi-2β and the coiled-coil region of RFP. Interestingly, confocal microscopic analyses revealed the co-localization of MCRS1, Mi-2β, RFP, and the rRNA transcription factor UBF in the nucleoli. We also found that MCRS1, Mi-2β, and RFP were associated with rDNA using a chromatin immunoprecipitation assay. Finally, we showed that MCRS1, Mi-2β, and RFP up-regulated transcriptional activity of the rDNA promoter and that ribosomal RNA transcription was repressed when MCRS1, Mi-2β, and RFP expression was reduced using siRNA. These results indicated that Mi-2β and RFP, known to be involved in transcriptional repression in the nucleus, co-localize with MCRS1 in the nucleolus and appear to activate the rRNA transcription.

Original languageEnglish
Pages (from-to)39436-39447
Number of pages12
JournalJournal of Biological Chemistry
Volume280
Issue number47
DOIs
Publication statusPublished - 25-11-2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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