Identification of cis- and trans-acting factors involved in the localization of MALAT-1 noncoding RNA to nuclear speckles

RNA. 2012 Apr;18(4):738-51. doi: 10.1261/rna.028639.111. Epub 2012 Feb 21.

Abstract

MALAT-1 noncoding RNA is localized to nuclear speckles despite its mRNA-like characteristics. Here, we report the identification of several key factors that promote the localization of MALAT-1 to nuclear speckles and also provide evidence that MALAT-1 is involved in the regulation of gene expression. Heterokaryon assays revealed that MALAT-1 does not shuttle between the nucleus and cytoplasm. RNAi-mediated repression of the nuclear speckle proteins, RNPS1, SRm160, or IBP160, which are well-known mRNA processing factors, resulted in the diffusion of MALAT-1 to the nucleoplasm. We demonstrated that MALAT-1 contains two distinct elements directing transcripts to nuclear speckles, which were also capable of binding to RNPS1 in vitro. Depletion of MALAT-1 represses the expression of several genes. Taken together, our results suggest that RNPS1, SRm160, and IBP160 contribute to the localization of MALAT-1 to nuclear speckles, where MALAT-1 could be involved in regulating gene expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Nucleus / metabolism*
  • DNA Primers
  • Down-Regulation
  • HeLa Cells
  • Humans
  • RNA Interference
  • RNA, Long Noncoding
  • RNA, Untranslated / genetics
  • RNA, Untranslated / metabolism*

Substances

  • DNA Primers
  • MALAT1 long non-coding RNA, human
  • RNA, Long Noncoding
  • RNA, Untranslated