A repressor element in the 5'-untranslated region of human Pax5 exon 1A

Five members of the RecQ helicase family, RECQL, WRN, BLM, RTS and RECQL5, have been found in human and three of them (WRN, BLM and RTS) were disclosed to be the genes responsible for Werner, Bloom and Rothmund–Thomson syndromes, respectively. RECQL5 (RecQ helicase protein-like 5) was isolated as the fifth member of the family in humans through a search of homologous expressed sequence tags. The gene is expressed with at least three alternative splicing products, , β and γ. Here, we isolated mouse RECQL5β and determined the DNA sequence of full-length cDNA as well as the genome organization and chromosome locus. The mouse RECQL5β gene consists of 2949 bp coding 982 amino acid residues. Comparison of amino acid sequence among human (Homo sapiens), mouse (Mus musculus), Drosophila melanogaster and Caenorhabditis elegans RECQL5β homologs revealed three portions of highly conserved regions in addition to the helicase domain. Nineteen exons are dispersed over 40 kbp in the genome and all of the acceptor and donor sites for the splicing of each exon conform to the GT/AG rule. The gene is localized to the mouse chromosome 11E2, which has a syntenic relation to human 17q25.2-q25.3 where human RECQL5β exists. Our genetic characterizations of the mouse RECQL5β gene will contribute to functional studies on the RECQL5β products.