title: Functional divergence among silkworm antimicrobial peptide paralogs by the activities of recombinant proteins and the induced expression profiles.
abstract: Antimicrobial peptides are small-molecule proteins that are usually encoded by multiple-gene families. They play crucial roles in the innate immune response, but reports on the functional divergence of antimicrobial peptide gene families are rare. In this study, 14 paralogs of antimicrobial peptides belonging to cecropin, moricin and gloverin families were recombinantly expressed in pET expression systems. By antimicrobial activity tests, peptides representing paralogs in the same family of cecropin and moricin families, displayed remarkable differences against 10 tested bacteria. The evolutionary rates were relatively fast in the two families, which presented obvious functional divergence among paralogs of each family. Four peptides of gloverin family had similar antimicrobial spectrum and activity against tested bacteria. The gloverin family showed similar antimicrobial function and slow evolutionary rates. By induced transcriptional activity, genes encoding active antimicrobial peptides were upregulated at obviously different levels when silkworm pupae were infected by three types of microbes. Association analysis of antimicrobial activities and induced transcriptional activities indicated that the antimicrobial activities might be positively correlated with induced transcriptional activities in the cecropin and moricin families. These results suggest that representative BmcecB6, BmcecD and Bmmor as the major effector genes have broad antimicrobial spectrum, strong antimicrobial activity and high microbe-induced expression among each family and maybe play crucial roles in eliminating microbial infection.
authors.affiliation: Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China.
authors.forename: Wanying
authors.initials: W
authors.lastname: Yang
authors.forename: Tingcai
authors.initials: T
authors.lastname: Cheng
authors.forename: Mingqiang
authors.initials: M
authors.lastname: Ye
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Deng
authors.forename: Huiyu
authors.initials: H
authors.lastname: Yi
authors.forename: Yadong
authors.initials: Y
authors.lastname: Huang
authors.forename: Xiang
authors.initials: X
authors.lastname: Tan
authors.forename: Dong
authors.initials: D
authors.lastname: Han
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.forename: Zhonghuai
authors.initials: Z
authors.lastname: Xiang
authors.forename: Yang
authors.initials: Y
authors.lastname: Cao
authors.forename: Qingyou
authors.initials: Q
authors.lastname: Xia
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D001483:Base Sequence; D012831:Bombyx / Q000187:drug effects / Q000235:genetics* / Q000382:microbiology; D004591:Electrophoresis, Polyacrylamide Gel; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D014644:Genetic Variation / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D005810:Multigene Family / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic / Q000187:drug effects; D014462:Ultrafiltration
chemical_list: D023181:Antimicrobial Cationic Peptides; D011994:Recombinant Proteins