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.