The Caenorhabditis elegans mucolipin-like gene cup-5 is essential for viability and regulates lysosomes in multiple cell types.
The misregulation of programmed cell death, or apoptosis, contributes to the pathogenesis of many diseases. We used Nomarski microscopy to screen for mutants containing refractile cell corpses in a C. elegans strain in which all programmed cell death is blocked and such corpses are absent. We isolated a mutant strain that accumulates refractile bodies resembling irregular cell corpses. We rescued this mutant phenotype with the C. elegans mucolipidosis type IV (ML-IV) homolog, the recently identified cup-5 (coelomocyte-uptake defective) gene. ML-IV is a human autosomal recessive lysosomal storage disease characterized by psychomotor retardation and ophthalmological abnormalities. Our null mutations in cup-5 cause maternal-effect lethality. In addition, cup-5 mutants contain excess lysosomes in many and possibly all cell types and contain lamellar structures similar to those observed in ML-IV cell lines. The human ML-IV gene is capable of rescuing both the maternal-effect lethality and the lysosome-accumulation abnormality of cup-5 mutants. cup-5 mutants seem to contain excess apoptotic cells as detected by staining with terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling. We suggest that the increased apoptosis seen in cup-5 mutants is a secondary consequence of the lysosomal defect, and that abnormalities in apoptosis may be associated with human lysosomal storage disorders.
Hersh
Bradley M
BM
Howard Hughes Medical Institute, Department of Biology, 68-425, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Hartwieg
Erika
E
Horvitz
H Robert
HR
D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000502:physiology; D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D020287:In Situ Nick-End Labeling; D008247:Lysosomes / Q000502:physiology*; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D009154:Mutation
C426649:CUP-5 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; D008565:Membrane Proteins