title: NUC-1, a caenorhabditis elegans DNase II homolog, functions in an intermediate step of DNA degradation during apoptosis.
abstract: One hallmark of apoptosis is the degradation of chromosomal DNA. We cloned the Caenorhabditis elegans gene nuc-1, which is involved in the degradation of the DNA of apoptotic cells, and found that nuc-1 encodes a homolog of mammalian DNase II. We used the TUNEL technique to assay DNA degradation in nuc-1 and other mutants defective in programmed cell death and discovered that TUNEL labels apoptotic cells only during a transient intermediate stage. Mutations in nuc-1 allowed the generation of TUNEL-reactive DNA but blocked the conversion of TUNEL-reactive DNA to a subsequent TUNEL-unreactive state. Completion of DNA degradation did not occur in the absence of cell-corpse engulfment. Our data suggest that the process of degradation of the DNA of a cell corpse occurs in at least three distinct steps and requires activities provided by both the dying and the engulfing cell.
authors.affiliation: Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 USA.
authors.forename: Y C
authors.initials: YC
authors.lastname: Wu
authors.forename: G M
authors.initials: GM
authors.lastname: Stanfield
authors.forename: H R
authors.initials: HR
authors.lastname: Horvitz
mesh_terms: D000818:Animals; D017209:Apoptosis; D017173:Caenorhabditis elegans / Q000196:embryology* / Q000235:genetics; D002874:Chromosome Mapping; D018509:DNA, Helminth / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000166:cytology* / Q000502:physiology; D004706:Endodeoxyribonucleases / Q000235:genetics / Q000378:metabolism*; D020287:In Situ Nick-End Labeling; D007814:Larva; D008322:Mammals
chemical_list: D018509:DNA, Helminth; D004706:Endodeoxyribonucleases; C019329:deoxyribonuclease II