A knock-in translational reporter for NLP-29 reveals AMP secretion to the apical extracellular matrices following epidermal damage in Caenorhabditis elegans

Antimicrobial peptides (AMPs) are small proteins produced and secreted as part of the innate immune response to infection and wounding. They target pathogens and can also function as signalling molecules, for example, promoting sleep in response to injury in <i>C. elegans</i> . A transcriptional reporter transgene for <i>nlp-29</i> has been pivotal in studying AMP gene expression and regulation, but to understand AMPs antimicrobial and signalling roles, protein expression and trafficking needs to be monitored. We have now created a knock-in translational reporter allele for <i>nlp-29</i> , with NLP-29 fused to mKate2, that enables visualisation of this secreted AMP. Using the NLP-29::mKate2 reporter, we demonstrate that NLP-29 is secreted into the cuticle upon genetic or physical cuticle damage. NLP-29::mKate2 will therefore be a valuable tool for visualising the secretion of this peptide in <i>C. elegans</i> and thus to dissect the different roles of this key AMP.