Four subunit a isoforms of Caenorhabditis elegans vacuolar H+-ATPase. Cell-specific expression during development.
We have identified four genes (vha-5, vha-6, vha-7, and unc-32) coding for vacuolar-type proton-translocating ATPase (V-ATPase) subunit a in Caenorhabditis elegans, the first example of four distinct isoforms in eukaryotes. Their products had nine putative transmembrane regions, exhibited 43-60% identity and 62-84% similarity with the bovine subunit a1 isoform, and retained 11 amino acid residues essential for yeast V-ATPase activity (Leng, X. H., Manolson, M. F., and Forgac, M. (1998) J. Biol. Chem. 273, 6717-6723). The similarities, together with the results of immunoprecipitation, suggest that these isoforms are components of V-ATPase. Transgenic and immunofluorescence analyses revealed that these genes were strongly expressed in distinct cells; vha-5 was strongly expressed in an H-shaped excretory cell, vha-6 was strongly expressed in intestine, vha-7 was strongly expressed in hypodermis, and unc-32 was strongly expressed in nerve cells. Furthermore, the vha-7 and unc-32 genes were also expressed in the uteri of hermaphrodites. RNA interference analysis showed that the double-stranded RNA for unc-32 caused embryonic lethality similar to that seen with other subunit genes (vha-1, vha-4, and vha-11) (Oka, T., and Futai, M. (2000) J. Biol. Chem. 275, 29556-29561). The progenies of worms injected with the vha-5 or vha-6 double-stranded RNA became died at a specific larval stage, whereas the vha-7 double-stranded RNA showed no effect on development. These results suggest that V-ATPases with these isoforms generate acidic compartments essential for worm development in a cell-specific manner.
Oka
T
T
Division of Biological Sciences, Institute of Scientific and Industrial Research, Osaka University, Japan.
Toyomura
T
T
Honjo
K
K
Wada
Y
Y
Futai
M
M
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D017173:Caenorhabditis elegans / Q000196:embryology / Q000201:enzymology* / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D012734:Disorders of Sex Development; D004625:Embryo, Nonmammalian; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D007422:Intestines / Q000166:cytology / Q000201:enzymology; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics; D008297:Male; D008969:Molecular Sequence Data; D009420:Nervous System / Q000166:cytology / Q000201:enzymology; D009928:Organ Specificity; D021122:Protein Subunits; D017494:Proton Pumps / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012330:RNA, Double-Stranded / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000166:cytology / Q000201:enzymology; D014599:Uterus / Q000166:cytology / Q000201:enzymology; D025262:Vacuolar Proton-Translocating ATPases
D029742:Caenorhabditis elegans Proteins; D007527:Isoenzymes; D008164:Luminescent Proteins; D021122:Protein Subunits; D017494:Proton Pumps; D012330:RNA, Double-Stranded; D011993:Recombinant Fusion Proteins; C506985:vha-11 protein, C elegans; C506986:vha-2 protein, C elegans; C506987:vha-3 protein, C elegans; D049452:Green Fluorescent Proteins; D025262:Vacuolar Proton-Translocating ATPases; C506981:unc-32 protein, C elegans; D006180:Proton-Translocating ATPases