Fate of the nuclear lamina during Caenorhabditis elegans apoptosis.
Invertebrates and in Drosophila, lamins and lamin-associated proteins are primary targets for cleavage by caspases. Eliminating mammalian lamins causes apoptosis, whereas expressing mutant lamins that cannot be cleaved by caspase-6 delay apoptosis. Caenorhabditis elegans has a single lamin protein, Ce-lamin, and a caspase, CED-3, that is responsible for most if not all somatic apoptosis. In this study we show that in C. elegans embryos induced to undergo apoptosis Ce-lamin is degraded surprisingly late. In such embryos CED-4 translocated to the nuclear envelope but the cytological localization of Ce-lamin remained similar to that in wild-type embryos. TUNEL labeling indicated that Ce-lamin was degraded only after DNA is fragmented. Ce-lamin, Ce-emerin, or Ce-MAN1 were not cleaved by recombinant CED-3, showing that these lamina proteins are not substrates for CED-3 cleavage. These results suggest that lamin cleavage probably is not essential for apoptosis in C. elegans.
Tzur
Yonatan B
YB
Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Israel.
Hersh
Bradley M
BM
Horvitz
H Robert
HR
Gruenbaum
Yosef
Y
D000818:Animals; D017209:Apoptosis; D017173:Caenorhabditis elegans / Q000378:metabolism / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins; D020169:Caspases / Q000096:biosynthesis; D002467:Cell Nucleus / Q000473:pathology* / Q000502:physiology*; D019084:Fluorescent Antibody Technique, Indirect; D020287:In Situ Nick-End Labeling; D034882:Lamins / Q000378:metabolism / Q000502:physiology*; D008565:Membrane Proteins / Q000096:biosynthesis; D034881:Nuclear Lamina / Q000502:physiology*; D009687:Nuclear Proteins / Q000096:biosynthesis; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding
D029742:Caenorhabditis elegans Proteins; D034882:Lamins; D008565:Membrane Proteins; D009687:Nuclear Proteins; C485768:lem-2 protein, C elegans; D020169:Caspases; C089223:ced-3 protein, C elegans