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Author Notes:

Corresponding author: Department of Biology, Emory University, 1510 Clifton Rd. NE, Atlanta, GA 30322. E-mail: bioslh@emory.edu

Supporting information is available online at http://www.genetics.org/content/suppl/2012/03/23/genetics.112.139618.DC1.

The first four authors contributed equally to this work and are listed alphabetically.

PDH Present address: Department of Cellular and Molecular Pharmacology, University of California, 1700 4th St., MC 2530, San Francisco, CA 94158.

KLHH Present address: Powell Gene Therapy Center, Department of Pediatrics, University of Florida, Gainesville, FL 32610.

RMW Present address: Genentech Inc., 1 DNA Way, South San Francisco, CA 94080.

TLK Present address: Department of Biology, 1035 Kirby Dr., University of Minnesota, Duluth, MN 55812.

GZ Present address: Pathway Genomics Corporation, 4045 Sorrento Valley Blvd., San Diego, CA, 92121.

SC Present address: National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341.

Subject:

Research Funding:

This work was supported by NIH grants GM040697 and GM082932 to S.W.L. and R43 GM071317 to Abeome Inc.

Keywords:

  • V-ATPase
  • lysosomes
  • SPE-5
  • spermatogenesis
  • Caenorhabditis elegans

Developmental Genetics of Secretory Vesicle Acidification During Caenorhabditis elegans Spermatogenesis

Tools:

Journal Title:

Genetics

Volume:

Volume 191, Number 2

Publisher:

, Pages 477-491

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Secretory vesicles are used during spermatogenesis to deliver proteins to the cell surface. In Caenorhabditis elegans, secretory membranous organelles (MO) fuse with the plasma membrane to transform spermatids into fertilization-competent spermatozoa. We show that, like the acrosomal vesicle of mammalian sperm, MOs undergo acidification during development. Treatment of spermatids with the V-ATPase inhibitor bafilomycin blocks both MO acidification and formation of functional spermatozoa. There are several spermatogenesis-defective mutants that cause defects in MO morphogenesis, including spe-5. We determined that spe-5, which is on chromosome I, encodes one of two V-ATPase B paralogous subunits. The spe-5 null mutant is viable but sterile because it forms arrested, multi-nucleate spermatocytes. Immunofluorescence with a SPE-5-specific monoclonal antibody shows that SPE-5 expression begins in spermatocytes and is found in all subsequent stages of spermatogenesis. Most SPE-5 is discarded into the residual body during spermatid budding, but a small amount remains in budded spermatids where it localizes to MOs as a discrete dot. The other V-ATPase B subunit is encoded by vha-12, which is located on the X chromosome. Usually, spe-5 mutants are self-sterile in a wild-type vha-12 background. However, an extrachromosomal transgene containing wild-type vha-12 driven by its own promoter allows spe-5 mutant hermaphrodites to produce progeny, indicating that VHA-12 can at least partially substitute for SPE-5. Others have shown that the X chromosome is transcriptionally silent in the male germline, so expression of the autosomally located spe-5 gene ensures that a V-ATPase B subunit is present during spermatogenesis.

Copyright information:

© 2012 by the Genetics Society of America

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