Three vha genes encode proteolipids of Caenorhabditis elegans vacuolar-type ATPase. Gene structures and preferential expression in an H-shaped excretory cell and rectal cells.
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-type H+-ATPase) genes in Caenorhabditis elegans encode putative 16-kDa proteolipids and are tandemly localized on chromosome III. The vha-2 gene 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.
Oka
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T
Department of Molecular Cell Biology, Division of Biological Science, Institute of Scientific and Industrial Research, Osaka University, Osaka 567, Japan.
Yamamoto
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Futai
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M
D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000201:enzymology / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D015971:Gene Expression Regulation, Enzymologic; D008969:Molecular Sequence Data; D011510:Proteolipids / Q000235:genetics*; D006180:Proton-Translocating ATPases / Q000235:genetics*; D012007:Rectum / Q000166:cytology / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D025262:Vacuolar Proton-Translocating ATPases
C506980:Atp6v0b protein, mouse; D029742:Caenorhabditis elegans Proteins; D011510:Proteolipids; C506985:vha-11 protein, C elegans; C506986:vha-2 protein, C elegans; C506987:vha-3 protein, C elegans; D025262:Vacuolar Proton-Translocating ATPases; C506981:unc-32 protein, C elegans; D006180:Proton-Translocating ATPases