tailieunhanh - Báo cáo khoa học: Identification, structure and differential expression of novel pleurocidins clustered on the genome of the winter flounder, Pseudopleuronectes americanus (Walbaum)

Antimicrobial peptides form one of the first lines of defense against invading pathogens by killing the microorganisms and/ormobilizing the host innate immune system. Although over 800 antimicrobial peptides have been isolated from many different species, especially insects, few have been reported frommarinefish. Sequenceanalysisof twogenomic clones ( and kb) from the winter flounder, Pseudopleuronectes americanus(Walbaum) resulted in the identification of multiple clustered genes for novel pleuro-cidin-like antimicrobial peptides | Eur. J. Biochem. 270 3720-3730 2003 FEBS 2003 doi j Identification structure and differential expression of novel pleurocidins clustered on the genome of the winter flounder Pseudopleuronectes americanus Walbaum Susan E. Douglas Aleksander Patrzykat Jennifer Pytyck and Jeffrey W. Gallant Institute for Marine Biosciences Halifax Nova Scotia Canada Antimicrobial peptides form one of the first lines of defense against invading pathogens by killing the microorganisms and or mobilizing the host innate immune system. Although over 800 antimicrobial peptides have been isolated from many different species especially insects few have been reported from marine fish. Sequence analysis of two genomic clones and kb from the winter flounder Pseudopleuronectes americanus Walbaum resulted in the identification of multiple clustered genes for novel pleuro-cidin-like antimicrobial peptides. Four genes and three pseudogenes Y are encoded in these clusters all of which have similar intron exon boundaries but specify putative antimicrobial peptides differing in sequence. Pseudogenes are easily detectable but have incorrect initiator codons ACG and often contain a frameshift s . Potential promoters and binding sites for transcription factors implicated in regulation of expression of immune-related genes have been identified in upstream regions by comparative genomics. Using reverse transcription-PCR assays we have shown for the first time that each gene is expressed in a tissuespecific and developmental stage-specific manner. In addition synthetic peptides based on the sequences of both genes and pseudogenes have been produced and tested for antimicrobial activity. These data can be used as a basis for prediction of antimicrobial peptide candidates for both human and nonhuman therapeutants from genomic sequences and will aid in understanding the evolution and transcriptional regulation of expression of these peptides. Keywords antimicrobial .