B. Vanhille et al., THE UBIQUITOUS VA68 ISOFORM OF SUBUNIT-A OF THE VACUOLAR H-ATPASE IS HIGHLY EXPRESSED IN HUMAN OSTEOCLASTS(), Biochemical and biophysical research communications, 214(3), 1995, pp. 1108-1113
The 67-kDa subunit A of the vacuolar-type H+-ATPase carries the high a
ffinity ATP binding site and together with the 57-kDa subunit B forms
the catalytic domain. Two isoforms of subunit A, VA68 and HO68, were c
loned from an osteoclastoma cDNA library. We have analyzed their respe
ctive expression patterns in different tissues by RNAse A protection a
nd in situ hybridization. The HO68 isoform was found to be present onl
y in the tumor originally used to construct the cDNA library, whereas
the ubiquitous VA68 RNA isoform was detected in large osteoclastic cel
ls, as well as in brain and kidney, by RNAse protection assay. Further
more, we localised the strong signal observed in osteoclastoma RNA to
the large osteoclastic cells by in situ hybridisation. These findings
suggest that the subunit A highly expressed in human osteoclasts is th
e ubiquitous isoform, VA68. (C) 1995 Academic Press, Inc.