T. Morinaga et al., CLONING AND CHARACTERIZATION OF THE GENE ENCODING HUMAN OSTEOPROTEGERIN OSTEOCLASTOGENESIS-INHIBITORY FACTOR/, European journal of biochemistry, 254(3), 1998, pp. 685-691
The human osteoprotegerin (OPG)-osteoclastogenesis-inhibitory factor (
OCIF) gene has been cloned and characterized. The OPG-OCIF gene is a s
ingle-copy gene consisting of five exons, and spans 29 kb of the human
genome. All the exon/intron boundaries comply with the GT/AG rule. Th
e translation-termination codon is present in exon 5 and a typical pol
y(A)-addition signal resides 173-nucleotides downstream of the transla
tion-termination codon. A major transcription-initiation site is prese
nt 67-nucleotides upstream of the initiation ATG codon. Two minor site
s are present further upstream. The 4.2-kb and 6.5-kb transcripts dete
cted in IMR-90 cells were found to contain the 3'-half of intron 2 and
the entire intron 2, respectively. In the OPG-OCIF gene, a single int
ron divides the stretch that encode four Cys-rich motifs, implying div
ersity from the other members of the tumor necrosis factor receptor (T
NFR) family. Two death domain homologous regions (DDHs) present in tan
dem in OPG-OCIF are encoded separately by exons 4 and 5. The conservat
ion of amino-acid sequences suggests that exon 4 is produced by a dupl
ication of a portion of exon 5.