Analysis and Inactivation of vha55, the Gene Encoding the Vacuolar ATPase B-subunit in Drosophila melanogaster Reveals a Larval Lethal Phenotype

doi:10.1074/jbc.271.48.30677

Analysis and Inactivation of vha55, the Gene Encoding the Vacuolar ATPase B-subunit in Drosophila melanogaster Reveals a Larval Lethal Phenotype*

From the Division of Molecular Genetics, Institute for Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom

^‡ To whom correspondence should be addressed:
Division of Molecular Genetics, Pontecorvo Bldg., University of Glasgow, Glasgow G11 6NU, UK.
Tel.: 44-41-330-4616; Fax: 44-41-330-5994; E-mail: j.a.t.dow{at}bio.gla.ac.uk.

Abstract

Vacuolar ATPases play major roles in endomembrane and plasma membrane proton transport in eukaryotes. A Drosophila melanogaster cDNA encoding vha55, the 55-kDa vacuolar ATPase (V-ATPase) regulatory B-subunit, was characterized and mapped to 87C2-4 on chromosome 3R. A fly line was identified that carried a single lethal P-element insertion within the coding portion of gene, and its LacZ reporter gene revealed elevated expression in Malpighian tubules, rectum, antennal palps, and oviduct, regions where V-ATPases are believed to play a plasma membrane, rather than an endomembrane, role. The P-element vha55 insertion was shown to be allelic to a known lethal complementation group l(3)SzA (= l(3)87Ca) at 87C, for which many alleles have been described previously. Deletions of the locus have been shown to be larval lethal, whereas point mutations show a range of phenotypes from subvital to embryonic lethal, implying that severe alleles confer a partial dominant negative phenotype. The P-element null allele of vha55 was shown also to suppress ectopic sex combs in Polycomb males, suggesting that transcriptional silencing may be modulated by genes other than those with known homeotic or DNA binding functions.

Footnotes

↵* This work was supported by Medical Research Council Grant G9120579CB, a Nuffield Foundation Research Fellowship, and a Royal Society Grant (to J. A. T. D.) and by general Funds of the University of Glasgow. The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

ATPase

adenosine triphosphatase

V-ATPase

vacuolar ATPase

PCR

polymerase chain reaction

bp

base pair(s)

kb

kilobase(s) or 1000 bp

Pc

Polycomb

MOPS

4-morpholinepropanesulfonic acid.
↵² Y. Guo, unpublished observations.
- Received March 11, 1996.
- Revision received July 3, 1996.