Identification and chromosome mapping of the mouse homologue of the human gene (DDX6) that encodes a putative RNA helicase of the DEAD box protein family

The human DDX6 gene (alias RCK) at chromosome some 11 band q23 was identified through the study of the breakpoint of t(11;14)(q23;q32) translocation in a B-cell lymphoma cell liner RC-K8, DDX6 encodesa DEAD box protein/RNA RNA helicase, Positive mouse genomic and cDNA recombinant clones were obtained by screening mouse B-tell genomic and cDNA libraries with a human DDX6 cDNA probe, The deduced amino acid sequence of an open reading frame from a cDNA clone revealed a protein with 92.5% identity to human ddx6/p54. All positive mouse genomic recombinant clones, and cDNA clones containing mouse Ddx6 (previous gene symbol: Rck), were localized by fluorescent in situ hybridization to band B of mouse Chromosome 9, a region showing conserved linkage homology to human chromosome 11 band q23. Mouse Ddx6 was localized to the region between Ncam and D9Mit45 by molecular linkage analysis, A 7.5-kb mRNA and a 54-kDa protein were identified as mouse Ddx6 gene products which are similar in size to products of the human DDXG gene, as shown by Northern and Western blot analyses.