title: cDNA cloning of a mannose-binding lectin-associated serine protease (MASP) gene from hagfish (Eptatretus burgeri).
abstract: Hagfish, agnathan cyclostome, is the most primitive extant vertebrate and its complement (C) system seems to be a primordial system in comparison with a well-developed C system in gnathostome vertebrates. From a phylogenic perspective of defense mechanisms, we have isolated complement C3 from the serum of hagfish (Eptatretus burgeri). In this study, we first attempted to identify a hagfish Bf or C2 as a C3 convertase by RT-PCR using degenerative primers designed on the basis of the conserved amino acid stretches among the several kinds of serine proteases. Contrary to our expectation, homology search of cloned RT-PCR product suggested that there was a partial cDNA encoding the homologue of neither Bf nor C2 but a mannose-binding lectin-associated serine protease (MASP). Analyses of a full-length cDNA clone isolated from a hagfish liver cDNA library by using the partial cDNA as a probe indicated that this cDNA encoded hagfish MASP 1. This evidence strongly suggests that the hagfish defends itself against pathogens at least by the complement system composed of lectin pathway.
authors.affiliation: Department of Health Sciences, Faculty of Human Culture and Science, Prefectural University of Hiroshima, Ujina-Higashi, Hiroshima 734-8558, Japan.
authors.forename: Liqiu
authors.initials: L
authors.lastname: Song
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Takamune
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Sugawara
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Fujii
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D016000:Cluster Analysis; D003167:Complement Activation / Q000235:genetics; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics*; D040461:Gene Components; D006196:Hagfishes / Q000235:genetics*; D050606:Mannose-Binding Protein-Associated Serine Proteases / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D050606:Mannose-Binding Protein-Associated Serine Proteases