The presenilin protein family member SPE-4 localizes to an ER/Golgi derived organelle and is required for proper cytoplasmic partitioning during Caenorhabditis elegans spermatogenesis.
During Caenorhabditis elegans spermatogenesis, asymmetric partitioning of cellular components principally occurs via ER/Golgi-derived organelles, named fibrous body-membranous organelles. In C. elegans spe-4 mutants, morphogenesis of fibrous body-membranous organelle complexes is defective and spermatogenesis arrests at an unusual cellular stage with four haploid nuclei within a common cytoplasm. The spe-4 encoded integral membrane protein is a diverged member of the presenilin family implicated in early onset Alzheimer's disease. Specific antisera were used to show that SPE-4 resides within the fibrous body-membranous organelles membranes during wild-type spermatogenesis. Several spe-4 recessive mutants were examined for SPE-4 immunoreactivity and a deletion mutant lacks detectable SPE-4 while either of two missense mutants synthesize and localize immunoreactive SPE-4 within their fibrous body-membranous organelles. One of these missense mutations is located within a motif that is common to all presenilins. spe-4 mutants were also examined for other partitioning defects and tubulin was found to accumulate in unusual deposits close to the plasma membrane. These results suggest that wild-type SPE-4 is required for proper localization of macromolecules that are subject to asymmetric partitioning during spermatogenesis.
Arduengo
P M
PM
Graduate Program in Biochemistry, Emory University, Atlanta, Georgia 30322, USA.
Appleberry
O K
OK
Chuang
P
P
L'Hernault
S W
SW
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D017173:Caenorhabditis elegans / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins; D002451:Cell Compartmentation / Q000502:physiology*; D002455:Cell Division; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism*; D004252:DNA Mutational Analysis; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism* / Q000502:physiology*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D017354:Point Mutation; D017386:Sequence Homology, Amino Acid; D013091:Spermatogenesis / Q000502:physiology*; D013094:Spermatozoa / Q000378:metabolism / Q000502:physiology*; D014404:Tubulin / Q000378:metabolism
D000199:Actins; D000906:Antibodies; D029742:Caenorhabditis elegans Proteins; D008565:Membrane Proteins; D014404:Tubulin; C076714:spe-4 protein, C elegans