A pals-25 gain-of-function allele triggers systemic resistance against natural pathogens of C. elegans

PLoS Genet. 2022 Oct 3;18(10):e1010314. doi: 10.1371/journal.pgen.1010314. eCollection 2022 Oct.

Abstract

Regulation of immunity throughout an organism is critical for host defense. Previous studies in the nematode Caenorhabditis elegans have described an "ON/OFF" immune switch comprised of the antagonistic paralogs PALS-25 and PALS-22, which regulate resistance against intestinal and epidermal pathogens. Here, we identify and characterize a PALS-25 gain-of-function mutant protein with a premature stop (Q293*), which we find is freed from physical repression by its negative regulator, the PALS-22 protein. PALS-25(Q293*) activates two related gene expression programs, the Oomycete Recognition Response (ORR) against natural pathogens of the epidermis, and the Intracellular Pathogen Response (IPR) against natural intracellular pathogens of the intestine. A subset of ORR/IPR genes is upregulated in pals-25(Q293*) mutants, and they are resistant to oomycete infection in the epidermis, and microsporidia and virus infection in the intestine, but without compromising growth. Surprisingly, we find that activation of PALS-25 seems to primarily stimulate the downstream bZIP transcription factor ZIP-1 in the epidermis, with upregulation of gene expression in both the epidermis and in the intestine. Interestingly, we find that PALS-22/25-regulated epidermal-to-intestinal signaling promotes resistance to the N. parisii intestinal pathogen, demonstrating cross-tissue protective immune induction from one epithelial tissue to another in C. elegans.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Alleles
  • Animals
  • Basic-Leucine Zipper Transcription Factors / genetics
  • Caenorhabditis elegans Proteins* / metabolism
  • Caenorhabditis elegans* / metabolism
  • Gain of Function Mutation
  • Immunity, Innate / genetics
  • Mutant Proteins / genetics

Substances

  • Basic-Leucine Zipper Transcription Factors
  • Caenorhabditis elegans Proteins
  • Mutant Proteins