Molecular evolution and functional characterization of the Lamprey Mannose-binding Lectin-associated Serine Protease 1-1ike (L-MASP1-like)

Abstract Mannose-binding Lectin-associated Serine Proteases (MASPs) play important roles in the lectin pathway of complement system. In this study, a MASP homologous was cloned and characterized from lamprey. Homology comparison of MASP1 and MASP2 sequences from other species and phylogenetic analysis showed that the lamprey MASP gene is probably the MASP1 homologue and was named L-MASP1-like. There is no motif17 in L-MASP1-like just as MASP1. The exon composition and the synteny analysis of MASP2 gene was different from that of MASP1. Comparison of the exon numbers and the overlapping location between the exons and the structural domain indicated that L-MASP1-like had its own uniqueness. The adjacent genes of L-MASP1-like display great changes in the arrangement pattern compared with jawed vertebrates. L-MASP1-like was mainly detected in liver, intestine, and kidney. Expression of L-MASP1-like was up-regulated in liver after lamprey was challenged by S. aureus. L-MASP1-like was also up-regulated in liver, intestine, and kidney after Aeromonas, Shewanella, and LPS stimulation. Furthermore, the lamprey serum depleted of L-MASP1-like protein inhibited the apoptosis of MCF-7 cells revealed by flow cytometry analysis. In summary, this study provides a novel understanding of L-MASP1-like in the prospects of the molecular evolution, its potential role in lamprey immune response, and the involvement in promoting cell apoptosis.