CGC Bibliography Paper 5130

abf-1 and abf-2, ASABF-type antimicrobial peptide genes in Caenorhabditis elegans.

Kato Y, Aizawa T, Hoshino H, Kawano K, Nitta K, Zhang H

Medline:

11772394

Citation:

Biochemical Journal 361: 221-230 2002

Type:

ARTICLE

Genes:

abf-1 abf-2 glp-4

Abstract:

Two genes encoding the ASABF (Ascaris suum antibacterial factor)-type antimicrobial peptide, abf-1 and abf-2, were identified in Caenorhabditis elegans. Recombinant ABF-2 exhibited potent microbicidal activity against Gram-positive and Grain-negative bacteria, and yeasts. The tissue-specific distribution estimated by immunofluorescence staining and transgenic analysis of a gfp fusion gene (where GFP corresponds to green fluorescent protein) suggested that ABF-2 contributes to surface defence in the pharynx. abf-1 contains a single intron at a conserved position, suggesting that asabf and abf originated from a common ancestor. Both transcripts for abf-1 and abf-2 were detected as two distinct forms, i.e. spliced leader (SL)1-trans-spliced with a long 5'-untranslated region (UTR) and SL-less with a short 5'-UTR. A polycistronic precursor RNA encoding ABF-1 and ABF-2 was detected, suggesting that these genes form an operon. An 'opportunistic operon' model for regulation of abf genes, including the generation of short SL-less transcripts, is proposed. In conclusion, C. elegans should have an immune defence system due to the antimicrobial peptides. C. elegans can be a novel model for innate immunity. Furthermore, the combination of biochemical identification in Ascaris suum and homologue hunting in C. elegans should be a powerful method of finding rapidly evolved proteins, such as some immune-related molecules in