title: The rat and mouse homologues of MASP-2 and MAp19, components of the lectin activation pathway of complement.
abstract: Recently, we described two novel constituents of the multimolecular initiation complex of the mannan-binding lectin (MBL) pathway of complement activation, a serine protease of 76 kDa, termed MASP-2, and a MASP-2 related plasma protein of 19 kDa, termed MAp19. Upon activation of the MBL/MASPs/MAp19 complex, MASP-2 cleaves the fourth complement component C4, while the role of MAp19 within the MBL/MASP-1/MASP-2/MAp19 complex remains to be clarified. In humans, the mRNA species encoding MASP-2 (2.6 kb) and MAp19 (1.0 kb) arise by an alternative polyadenylation/splicing mechanism from a single structural MASP-2 gene. Here, we report the complete primary structures of the rat homologue of MASP-2 and of rat and mouse MAp19. We show that both MASP-2 and MAp19 are part of the rat MBL pathway activation complex and demonstrate their exclusively hepatic biosynthesis. Southern blot and PCR analyses of rat genomic DNA indicate that as in humans, rat MASP-2 and MAp19 are encoded by a single structural gene.
authors.affiliation: Department of Microbiology and Immunology, University of Leicester, United Kingdom.
authors.forename: C M
authors.initials: CM
authors.lastname: Stover
authors.forename: S
authors.initials: S
authors.lastname: Thiel
authors.forename: N J
authors.initials: NJ
authors.lastname: Lynch
authors.forename: W J
authors.initials: WJ
authors.lastname: Schwaeble
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D002352:Carrier Proteins / Q000096:biosynthesis / Q000097:blood / Q000737:chemistry* / Q000235:genetics; D003001:Cloning, Molecular; D037222:Collectins; D003167:Complement Activation; D015342:DNA Probes; D018076:DNA, Complementary / Q000032:analysis; D005091:Exons; D007438:Introns; D037102:Lectins / Q000276:immunology*; D008351:Mannans / Q000276:immunology; D050606:Mannose-Binding Protein-Associated Serine Proteases; D051379:Mice; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D051381:Rats; D017208:Rats, Wistar; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000096:biosynthesis / Q000097:blood / Q000737:chemistry* / Q000235:genetics
chemical_list: D002352:Carrier Proteins; D037222:Collectins; D015342:DNA Probes; D018076:DNA, Complementary; D037102:Lectins; D008351:Mannans; D012333:RNA, Messenger; C491340:MASP-2 protein, mouse; C105296:MASP2 protein, human; D050606:Mannose-Binding Protein-Associated Serine Proteases; D012697:Serine Endopeptidases