Noble tandem-repeat galectin of Manila clam Ruditapes philippinarum is induced upon infection with the protozoan parasite Perkinsus olseni.
The galectin family of lectins plays crucial roles in the innate immunity systems of vertebrates and invertebrates. Noble galectin (MCGal) was cloned from the marine invertebrate Ruditapes philippinarum and characterized. This protein has an open reading frame of 918 nucleotides, with 309 amino acid residues, and a predicted molecular weight of 33.9kDa. Similar to other galectins, MCGal has neither a signal peptide nor a transmembrane domain, but it contains tandemly repeated carbohydrate recognition domains (CRDs), with typical conserved motifs that are important for carbohydrate recognition. Carbohydrate recognition by the recombinant MCGal (rMCGal), as determined by hapten inhibition of hemagglutination, revealed that rMCGal has features common to the galectin family, i.e., significant affinity for galactose and N-acetylgalactosamine. MCGal mRNA expression was detected mainly in the heart, mantle, foot, adductor, palp, and siphon tissues. Immunohistochemistry (IHC) using an anti-MCGal antibody confirmed MCGal expression in these tissues and in hemocytes. Temporal expression of MCGal mRNA in Manila clams challenged with Perkinsus or Vibrio species was up-regulated as compared with non-challenged healthy clams. rMCGal agglutinated Vibrio tapetis, and agglutination was inhibited by incubation with alpha-lactose. rMCGal also bound to the surface of Perkinsus olseni. MCGal plays a crucial role in Manila clam defense, particularly with respect to pathogen recognition.
Kim
Jin Young
JY
Department of Biochemistry, College of Medicine, Cheju National University, Jeju 690-756, Republic of Korea.
Kim
Young Mee
YM
Cho
Somi K
SK
Choi
Kwang Sik
KS
Cho
Moonjae
M
D000595:Amino Acid Sequence; D000818:Animals; D049872:Bivalvia / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000469:parasitology*; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000235:genetics / Q000302:isolation & purification; D037161:Galectins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D008969:Molecular Sequence Data; D010679:Philippines; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D020080:Tandem Repeat Sequences; D014733:Vibrio / Q000187:drug effects / Q000472:pathogenicity
D018076:DNA, Complementary; D037161:Galectins; D012333:RNA, Messenger