Identification of cis- and trans-acting factors involved in the localization of MALAT-1 to nuclear speckles
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ABSTRACT: MALAT-1 is a long mammalian non-coding transcript of approximately 8500 nucleotides. It is localized to nuclear speckles despite its mRNA-like characteristics, which usually result in the export of transcripts to the cytoplasm. In the present study, we report the identification of several factors that influence the nuclear speckle localization of MALAT-1, and we 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, but is stably retained within the nucleus. Analysis of MALAT-1 fragments showed that MALAT-1 contains two distinct nuclear speckle-directing elements (between nucleotides 1961 to 3040 and 6008 to 7011 of the MALAT-1 sequence). The knockdown of the nuclear speckle proteins, RNPS1, SRm160 or IBP160, resulted in the diffusion of MALAT-1 to the nucleoplasm. In addition, we have demonstrated that depletion of MALAT-1 represses the expression of several genes. This repression of gene expression also occurs in response to the delocalization of MALAT-1 from the nuclear speckles. These results suggest that RNPS1, SRm160 and IBP160 contribute to the localization of MALAT-1 to nuclear speckles where it is involved in regulating gene expression
ORGANISM(S): Homo sapiens
PROVIDER: GSE20506 | GEO | 2010/06/02
SECONDARY ACCESSION(S): PRJNA125093
REPOSITORIES: GEO
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