title: F-type lectin involved in defense against bacterial infection in the pearl oyster (Pinctada martensii).
abstract: In invertebrates and vertebrates, carbohydrate-binding proteins (lectins) play an important role in innate immunity against microbial invasion. In the present study, we report the cloning of an F-type lectin (designated as PmF-lectin) from pearl oyster (Pinctada martensii) using a combination of expression sequence tag (EST) analysis and rapid amplification of cDNA ends (RACE) PCR. The full-length cDNA of PmF-lectin contains an open reading frame (ORF) of 579 bp coding for192 amino acids. The deduced polypeptide possesses six conserved residues of the F-lectin family critical for the formation of disulfide bonds (Cys⁴³-Cys¹⁴³, Cys⁷⁵-Cys⁷⁶ and Cys¹⁰²-Cys¹¹⁹). Reverse transcription PCR (RT-PCR) and real-time quantitative PCR (qRT-PCR) analyses in adult tissues showed that the PmF-lectin mRNA was abundantly expressed in haemocytes and gill, moderately expressed in the mantle, and rarely expressed in other tissues tested. After challenge with Vibrio alginolyticus, expression of PmF-lectin mRNA in haemocytes was dramatically up-regulated, reaching the highest level (13-fold higher than that of the control group) at 3 h post challenge, and then dropped gradually. These results suggest that PmF-lectin is a member of the F-lectin family and is involved in the innate immune response in pearl oyster.
authors.affiliation: Key Laboratory of Marine Bio-resources Sustainable Utilization, CAS, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China.
authors.forename: Jinhui
authors.initials: J
authors.lastname: Chen
authors.forename: Shu
authors.initials: S
authors.lastname: Xiao
authors.forename: Ziniu
authors.initials: Z
authors.lastname: Yu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D037102:Lectins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D049911:Pinctada / Q000145:classification / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology*; D016415:Sequence Alignment; D013997:Time Factors; D044149:Vibrio alginolyticus / Q000502:physiology*
chemical_list: D037102:Lectins