Selective regulation of gene expression by nuclear factor 110, a member of the NF90 family of double-stranded RNA-binding proteins.
Members of the nuclear factor 90 (NF90) family of double-stranded RNA (dsRNA)-binding proteins have been implicated in several biological processes including the regulation of gene expression. cDNA sequences predict that the proteins have a functional nuclear localization signal and two dsRNA-binding motifs (dsRBMs), and are identical at their N termini. Isoforms are predicted to diverge at their C termini as well as by the insertion of four amino acid residues (NVKQ) between the two dsRBMs. In this study, we verified the expression of four of the isoforms by cDNA cloning and mass spectrometric analysis of proteins isolated from human cells. Cell fractionation studies showed that NF90 and its heteromeric partner, NF45, are predominantly nuclear and largely chromatin-associated. The C-terminally extended NF90 species, NF110, are almost exclusively chromatin-bound. Both NF110 isoforms are more active than NF90 isoforms in stimulating transcription from the proliferating cell nuclear antigen reporter in a transient expression system. NF110b, which carries the NVKQ insert, was identified as the strongest activator. It stimulated transcription of some, but not all, promoters in a fashion that suggested that it functions in concert with other transcription factors. Finally, we demonstrate that NF110b associates with the dsRBM-containing transcriptional co-activator, RNA helicase A, independently of RNA binding.
Reichman
Trevor W
TW
Department of Biochemistry and Molecular Biology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, 185 South Orange Ave., P.O. Box 1709, Newark, NJ 07103-1709, USA.
Parrott
Andrew M
AM
Fierro-Monti
Ivo
I
Caron
David J
DJ
Kao
Peter N
PN
Lee
Chee-Gun
CG
Li
Hong
H
Mathews
Michael B
MB
D000595:Amino Acid Sequence; D000818:Animals; D001324:Autoantigens / Q000378:metabolism; D053487:DEAD-box RNA Helicases; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D050778:NFATC Transcription Factors; D009363:Neoplasm Proteins; D051903:Nuclear Factor 45 Protein; D050779:Nuclear Factor 90 Proteins; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012313:RNA / Q000378:metabolism*; D020365:RNA Helicases / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
D001324:Autoantigens; D004268:DNA-Binding Proteins; C494013:ILF2 protein, human; C429643:ILF3 protein, human; D050778:NFATC Transcription Factors; D009363:Neoplasm Proteins; D051903:Nuclear Factor 45 Protein; D050779:Nuclear Factor 90 Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D012313:RNA; C098487:DHX9 protein, human; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases