Loss of DNase II function in the gonad is associated with a higher expression of antimicrobial genes in Caenorhabditis elegans

Hsiang Yu, Huey Jen Lai, Tai Wei Lin, Chang Shi Chen*, Szecheng J. Lo

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

10 Scopus citations

Abstract

Three waves of apoptosis shape the development of Caenorhabditis elegans. Although the exact roles of the three DNase II genes (nuc-1, crn-6 and crn-7), which are known to mediate degradation of apoptotic DNA, in the embryonic and larval phases of apoptosis have been characterized, the DNase II acting in the third wave of germ cell apoptosis remains undetermined. In the present study, we performed in vitro and in vivo assays on various mutant nematodes to demonstrate that NUC-1 and CRN-7, but not CRN-6, function in germ cell apoptosis. In addition, in situ DNA-break detection and anti-phosphorylated ERK (extracellular-signal-regulated kinase) staining illustrated the sequential and spatially regulated actions of NUC-1 and CRN-7, at the pachytene zone of the gonad and at the loop respectively. In line with the notion that UV-induced DNA fragment accumulation in the gonad activates innate immunity responses, we also found that loss of NUC-1 and CRN-7 lead to up-regulation of antimicrobial genes (abf-2, spp-1, nlp-29, cnc-2, and lys-7). Our observations suggest that an incomplete digestion of DNA fragments resulting from the absence of NUC-1 or CRN-7 in the gonad could induce the ERK signalling, consequently activating antimicrobial gene expression. Taken together, the results of the present study demonstrate for the first time that nuc-1 and crn-7 play a role in degrading apoptotic DNA in distinct sites of the gonad, and act as negative regulators of innate immunity in C. elegans.

Original languageEnglish
Pages (from-to)145-154
Number of pages10
JournalBiochemical Journal
Volume470
Issue number1
DOIs
StatePublished - 15 08 2015

Bibliographical note

Publisher Copyright:
© 2015 Authors; published by Portland Press Limited.

Keywords

  • Antimicrobial gene
  • Apoptosis
  • Caenorhabditis elegans
  • DNase II
  • Innate immunity

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