The novel helicase homologue DDX32 is down-regulated in acute lymphoblastic leukemia

We identified DDX32 as gene predicted to encode a 743 amino acid protein containing a helicase-like domain based on its homology to the conserved helicase domain of the DEAH family of helicases. The helicase domain of DDX32 has a novel sequence including a signature sequence of DDIH in motif II and several substitutions in other motifs. DDX32 has a murine orthologue and shares the presence of conserved sequences, other than the eight canonical helicase motifs, with DEAH helicases across species. Expression studies show that DDX32 is widespread but specifically down-regulated in acute lymphoblastic leukemias. DDX32 gene has 11 exons and is located on 10q26 chromosomal band. An alternatively spliced message lacking exon 4 in the coding region is present in several tissues. Our results suggest that DDX32 is a novel gene, which might play a role in normal and/or abnormal lymphopoiesis.