UNASSIGNED: Generation of DNA fragments is a hallmark of cell apoptosis and is executed within the dying cells (autonomous) or in the engulfing cells (non-autonomous). The TUNEL (terminal deoxynucleotidyl transferase @entity1977 nick end labelling) method is used as an in situ assay of apoptosis by labelling DNA fragments generated by caspase-associated DNase (CAD), but not those by the downstream DNase II. In the present study, we report a method of ToLFP (topoisomerase ligation fluorescence probes) for directly visualizing DNA fragments generated by DNase II in @entity2199 embryos. ToLFP analysis provided the first demonstration of a cell autonomous mode of DNase II activity in dying cells in @entity70070 embryos, which are defective in engulfing apoptotic bodies. Compared with the number of ToLFP signals between @entity70070 and wild-type (N2) embryos, a 30% increase in N2 embryos was found, suggesting that the ratio of non-autonomous and autonomous modes of DNase II was ~3-7. Among three DNase II mutant embryos ( @entity70071 , @entity70072 and @entity70073 ), @entity70071 embryos exhibited the least number of ToLFP. The ToLFP results confirmed the previous findings that @entity70071 is the major DNase II for degrading apoptotic DNA. To further elucidate @entity70071 's mode of action, @entity70071 -rescuing transgenic worms that ectopically express free or membrane-bound forms of @entity70071 fusion proteins were utilized. ToLFP analyses revealed that anteriorly expressed @entity70071 digests apoptotic DNA in posterior blastomeres in a non-autonomous and secretion-dependent manner. Collectively, we demonstrate that the ToLFP method can be used to differentiate the locations of blastomeres where DNase II acts autonomously or non-autonomously in degrading apoptotic DNA.

Autonomous and non-autonomous roles of DNase  II during cell death in XXXX embryos.

@entity70071 :: ('181174(Tax:6239)', 'Gene') :: ['NUC-1', 'nuc-1'] @entity2199 :: ('6239', 'Species') :: ['Caenorhabditis elegans'] @entity70072 :: ('176316(Tax:6239)', 'Gene') :: ['crn-6'] @entity1977 :: ('CHEBI:17625', 'Chemical') :: ['dUTP'] @entity70070 :: ('173064(Tax:6239)', 'Gene') :: ['ced-1'] @entity70073 :: ('176166(Tax:6239)', 'Gene') :: ['crn-7']
@entity2199 :: (6239,Species) :: ['C. elegans']
