Originally published as Genetics Published Articles Ahead of Print on September 2, 2005.

Genetics, Vol. 172, 145-158, January 2006, Copyright © 2006
doi:10.1534/genetics.105.047340

spe-10 Encodes a DHHC–CRD Zinc-Finger Membrane Protein Required for Endoplasmic Reticulum/Golgi Membrane Morphogenesis During Caenorhabditis elegans Spermatogenesis

Elizabeth J. Gleason*, Wesley C. Lindsey*,{dagger}, Tim L. Kroft*, Andrew W. Singson*,1 and Steven W. L'Hernault*,{dagger},2

{dagger} Program in Genetics and Molecular Biology, Graduate Division of Biological and Biomedical Sciences and * Department of Biology, Emory University, Atlanta, Georgia 30322

2 Corresponding author: Department of Biology, Emory University, 1510 Clifton Rd., Atlanta, GA 30322.
E-mail: bioslh{at}biology.emory.edu

C. elegans spermatogenesis employs lysosome-related fibrous body–membranous organelles (FB–MOs) for transport of many cellular components. Previous work showed that spe-10 mutants contain FB–MOs that prematurely disassemble, resulting in defective transport of FB components into developing spermatids. Consequently, spe-10 spermatids are smaller than wild type and contain defective FB–MO derivatives. In this article, we show that spe-10 encodes a four-pass integral membrane protein that has a DHHC–CRD zinc-finger motif. The DHHC–CRD motif is found in a large, diverse family of proteins that have been implicated in palmitoyl transfer during protein lipidation. Seven spe-10 mutants were analyzed, including missense, nonsense, and deletion mutants. An antiserum to SPE-10 showed significant colocalization with a known marker for the FB–MOs during wild-type spermatogenesis. In contrast, the spe-10(ok1149) deletion mutant lacked detectable SPE-10 staining; this mutant lacks a spe-10 promoter and most coding sequence. The spe-10(eb64) missense mutation, which changes a conserved residue within the DHHC–CRD domain in all homologues, behaves as a null mutant. These results suggest that wild-type SPE-10 is required for the MO to properly deliver the FB to the C. elegans spermatid and the DHHC–CRD domain is essential for this function.