Three vha Genes Encode Proteolipids ofCaenorhabditis elegans Vacuolar-type ATPase

• Published in: The Journal of biological chemistry Vol. 272; no. 39; pp. 24387 - 24392
• Main Authors: Oka, Toshihiko, Yamamoto, Ryuji, Futai, Masamitsu
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 26.09.1997; American Society for Biochemistry and Molecular Biology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.272.39.24387

The proteolipids of the vacuolar-type H+-ATPase (V-ATPase) are major components of the integral membrane sector. The vha-1 and vha-2(vacuolar-typeH+-ATPase) genes inCaenorhabditis elegans encode putative 16-kDa proteolipids and are tandemly localized on chromosome III. The vha-2gene has three exons, whereas vha-1 has no introns. The deduced amino acid sequences of the two genes exhibit about 60% identity with the homologues from yeast, mouse, and cow. The mRNAs of both vha genes are trans-spliced to spliced leaders, suggesting that these genes constitute a polycistronic transcriptional unit. The vha-4 gene consists of four exons and is very similar to the yeast VMA16 gene that codes for the 23-kDa proteolipid. This is the first example of three distinct V-ATPase proteolipids being identified in higher eukaryotes. Northern blot and transgenic analyses show that the three vha genes may be highly expressed in the H-shaped excretory cell, rectum, and a pair of cells posterior to the anus. These results suggest that the V-ATPase activity may be important for exporting toxic compounds or metabolic wastes in this organism.