title: Gene organization of a novel defensin of Ixodes ricinus: first annotation of an intron/exon structure in a hard tick defensin gene and first evidence of the occurrence of two isoforms of one member of the arthropod defensin family.
abstract: Antimicrobial peptides (defensins) are effectors of the immune system. Herein, we describe a novel Ixodes ricinus defensin gene(s), analyse its structure and compare it with other known antimicrobial peptides from different tick species. For the first time, an intron/exon structure is discovered in a hard-tick defensin gene. The intron/exon genomic organization of the gene is similar to the organization in Ornithodoros moubata, but not to that of the intronless defensins of Dermacentor variabilis and Ixodes scapularis. The analysis of the deduced amino acid sequences of different recombinants from the I. ricinus cDNA library reveals the presence of two defensin isoforms with three amino acid substitutions. Whether or not these substitutions affect the biological properties of the peptides is currently unknown. The expression of the defensin gene is strongly induced in the tick midgut after infection with Borrelia burgdorferi.
authors.affiliation: Faculty of Biological Sciences, University of South Bohemia and Biology Centre, Institute of Parasitology AS CR, Ceské Budejovice, Czech Republic. natasha@paru.cas.cz
authors.forename: N
authors.initials: N
authors.lastname: Rudenko
authors.forename: M
authors.initials: M
authors.lastname: Golovchenko
authors.forename: L
authors.initials: L
authors.lastname: Grubhoffer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D023082:Defensins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005091:Exons / Q000235:genetics*; D041981:Gastrointestinal Tract; D005786:Gene Expression Regulation; D007438:Introns / Q000235:genetics*; D018884:Ixodes / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000235:genetics
chemical_list: D023082:Defensins; D020033:Protein Isoforms