Cloning and characterization of the gene encoding mouse osteoclast differentiation factor

Osteoclast differentiation factor (ODF), a ligand for osteoclastogenesis in hibitory factor (OCIF)/ osteoprotegerin (OPG), is a member of the membrane- associated tumor necrosis factor (TNF) family and induces osteoclast-like c ell formation in vitro. In the present study, mouse ODF genomic clones were isolated and sequenced to determine their gene structure. The mouse ODF ge ne is a single copy gene consisting of five exons and spans approximately 4 0 kb of the mouse genome. The first exon encodes the intracellular and tran smembrane domains. The extracellular region of ODF containing the TNF homol ogous domain is encoded by exons 1 through 5. The translation-termination c odon and six polyadenylation signal residues are present in exon 5. A major transcription-initiation site is present 143 nucleotides upstream of the i nitiation-ATG codon. This genomic organization is similar to that of other members of the TNF family, especially the CD40 ligand. (C) 1999 Elsevier Sc ience B.V. All rights reserved.