MOLECULAR-CLONING AND CHARACTERIZATION OF A PUTATIVE NOVEL HUMAN OSTEOCLAST-SPECIFIC 116-KDA VACUOLAR PROTON PUMP SUBUNIT

A cDNA encoding a possible novel human 116-kDa polypeptide subunit of the osteoclastic proton pump (OC-116KDa) has been identified by differ ential screening of a human osteoclastoma cDNA library. The predicted sequence of OC-116KDa consists of 822 amino acids and is 46.9% and 47. 2% identical at the amino acid level to the 116-KDa polypeptide of the vacuolar proton pump of rat and bovine brain respectively. OC-116KDa mRNA was found at high levels in osteoclastomas by Northern analysis b ut was not detected in tumor stromal cells or in other tissues includi ng kidney, liver, skeletal muscle and brain. OC-116KDa mRNA was locali zed to multinucleated giant cells within the osteoclastoma tumor by in situ hybridization. (C) 1996 Academic Press, Inc.