Mouse RNA helicase II/Gu: cDNA and genomic sequences, chromosomal localization, and regulation of expression.
RNA helicase II/Gu (RH II/Gu) is a mammalian nucleolar RNA helicase previously identified using an autoimmune serum from a patient with watermelon stomach disease. RH II/Gu can unwind double-stranded RNA and can fold or introduce a secondary structure to a single-stranded RNA. These two enzymatic activities reside in two separate domains of the RH II/Gu molecule. The present study reports the molecular analysis of the cDNA and genomic sequences of the mouse RH II/Gu, its chromosomal localization, and the regulation of expression. The cDNA-derived amino acid sequence shows three tandem repeats at the NH(2)-terminal end of the protein, which are not conserved in the human homologue. Each repeat has 37 amino acids that are rich in basic residues. The helicase and foldase domains are highly conserved between the mouse and the human RH II/Gu. The basic promoter region of the mouse RH II/Gu gene is within 300 nucleotides upstream of a putative ATG initiation codon. Upstream of this promoter region is a silencer that represses transcription of the mouse RH II/Gu gene. This inhibitory region contains three 38-nucleotide repeats in tandem. The mouse RH II/Gu consists of 14 exons and 13 introns. The 3' flanking sequence of the gene contains three putative polyadenylation sites but only two sites are probably functional as shown by Northern blot analysis and 3' end sequences of mouse RH II/Gu cDNA in the EST database. These two alternative polyadenylation sites are approximately 240 and 2100 nucleotides from the TGA stop codon. Both mouse and human RH II/Gu genes are localized on chromosome 10. The availability of the mouse RH II/Gu gene will facilitate its functional analysis including creation of a mouse deficient in RH II/Gu protein.
Valdez
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BC
Department of Pharmacology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, 77030, USA. bvaldez@bcm.tmc.edu
Wang
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W
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002874:Chromosome Mapping / Q000662:veterinary*; D018076:DNA, Complementary; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics; D020365:RNA Helicases / Q000737:chemistry / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
D018076:DNA, Complementary; D020365:RNA Helicases