abf-1 and abf-2, ASABF-type antimicrobial peptide genes in Caenorhabditis elegans.
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 Gram-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 C. elegans.
Kato
Yusuke
Y
Department of Developmental Biology, National Institute of Agrobiological Sciences, Oowashi 1-2, Tsukuba, Ibaraki 305-8634, Japan. kato@affrc.go.jp
Aizawa
Tomoyasu
T
Hoshino
Hirokazu
H
Kawano
Keiichi
K
Nitta
Katsutoshi
K
Zhang
Hong
H
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism*; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D005455:Fluorescent Antibody Technique; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics*; D009876:Operon; D010455:Peptides; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics*
D000900:Anti-Bacterial Agents; D051792:Basic Helix-Loop-Helix Proteins; D029742:Caenorhabditis elegans Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D015801:Helminth Proteins; D010455:Peptides; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014157:Transcription Factors; C102532:ASABF protein, Ascaris suum; C486396:abf-1 protein, C elegans