Two mannose-binding lectin homologues and an MBL-associated serine protease are expressed in the gut epithelia of the urochordate species Ciona intestinalis.
The lectin complement pathway has important functions in vertebrate host defence and accumulating evidence of primordial complement components trace its emergence to invertebrate phyla. We introduce two putative mannose-binding lectin homologues (CioMBLs) from the urochordate species Ciona intestinalis. The CioMBLs display similarities with vertebrate MBLs and comprise a collagen-like region, alpha-helical coiled-coils and a carbohydrate recognition domain (CRD) with conserved residues involved in calcium and carbohydrate binding. Structural analysis revealed an oligomerization through interchain disulphide bridges between N-terminal cysteine residues and cysteines located between the neck region and the CRD. RT-PCR showed a tissue specific expression of CioMBL in the gut and by immunohistochemistry analysis we also demonstrated that CioMBL co-localize with an MBL-associated serine protease in the epithelia cells lining the stomach and intestine. In conclusion we present two urochordate MBLs and identify an associated serine protease, which support the concept of an evolutionary ancient origin of the lectin complement pathway.
Skjoedt
Mikkel-Ole
MO
Research Unit of Immunology and Microbiology, Institute of Medical Biology, Faculty of Health Science, University of Southern Denmark, Odense, Denmark. moskjoedt@health.sdu.dk
Palarasah
Yaseelan
Y
Rasmussen
Karina
K
Vitved
Lars
L
Salomonsen
Jan
J
Kliem
Anette
A
Hansen
Soren
S
Koch
Claus
C
Skjodt
Karsten
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002938:Ciona intestinalis / Q000201:enzymology* / Q000378:metabolism*; D004064:Digestive System / Q000201:enzymology / Q000378:metabolism; D004847:Epithelial Cells / Q000201:enzymology / Q000378:metabolism; D019143:Evolution, Molecular; D023061:Gene Order; D037601:Mannose-Binding Lectin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D050606:Mannose-Binding Protein-Associated Serine Proteases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016415:Sequence Alignment
D037601:Mannose-Binding Lectin; D050606:Mannose-Binding Protein-Associated Serine Proteases