Dnm3os, a gene that is transcribed into a non-coding RNA (ncRNA), contains three micro RNAs (miRNAs), miR-199a, miR-199a*, and miR-214, whose functions remain unknown in mammals. In this study, we introduced the lacZ gene into the Dnm3os locus to recapitulate its expression pattern and disrupt its function. Dnm3os(+/lacZ) heterozygous embryos showed beta-galactosidase activity, which reflected the authentic expression pattern of Dnm3os RNA. Most of the Dnm3os(lacZ/lacZ) homozygous pups died within one month of birth. After birth, Dnm3os(lacZ/lacZ) mice exhibited several skeletal abnormalities, including craniofacial hypoplasia, defects in dorsal neural arches and spinous processes of the vertebrae, and osteopenia. Importantly, the expression of miR-199a, miR-199a*, and miR-214 was significantly down-regulated in Dnm3os(lacZ/lacZ) embryos, supporting the assumption that Dnm3os serves as a precursor of these three miRNAs. Thus, Dnm3os has emerged as an miRNA-encoding gene that is indispensable for normal skeletal development and body growth in mammals.
(c) 2008 Wiley-Liss, Inc.