title: Molecular cloning, characterization and expression analysis of receptor for activated C kinase 1 (RACK1) from pearl oyster (Pinctada martensii) challenged with bacteria and exposed to cadmium.
abstract: Receptor for activated C kinase 1 (RACK1) is involved in superoxide anion generation and play an important role in the immune response. In the study, we cloned the full-length sequence of pearl oyster, Pinctada martensii, RACK1 (designated as PmRACK1) by a combination of expression sequence tag (EST) analysis and rapid amplification of cDNA ends (RACE). The full-length cDNA of PmRACK1 is 1176 bp in length, containing a 5' UTR of 83 bp, a 3' UTR of 139, and an open reading frame (ORF) of 954 bp encoding 317 amino acids. Analysis of protein domain features showed that the deduced polypeptide contain seven WD domains characteristic of RACK1 protein family. The tissue distribution of PmRACK1 in unchallenged pearl oysters and temporal expression pattern of PmRACK1 in pearl oysters challenged with bacteria and exposed to 0.1 ppm cadmium were analyzed by quantitative real-time PCR (qRT-PCR). The transcript was detected in all tissues tested, and the expression level was highest in hepatopancreas and lowest in adductor muscle. After challenge with bacteria, expression level of PmRACK1 in haemocytes was gradually decreased until 6 h post challenge, and then up-regulated over time. After exposure to cadmium, its expression level in gill decreased on 1 d post exposure, and then increased as time elapsed, and its expression level in hepatopancreas gradually decreased until 2 d post exposure, and then increased over time. These results suggested that PmRACK1 was involved in oxidative stress response caused by bacteria and cadmium and was a useful biomarker for cadmium exposure. The expression pattern of PmRACK1 in response to bacterial challenge also has a potential link with organism's immune response.
authors.affiliation: Key Laboratory of Marine Bio-resources Sustainable Utilization, CAS, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, Guangdong, China.
authors.forename: Jinhui
authors.initials: J
authors.lastname: Chen
authors.forename: Jifang
authors.initials: J
authors.lastname: Liu
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; D002104:Cadmium / Q000633:toxicity*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D043143:Hepatopancreas / Q000378:metabolism; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D049911:Pinctada / Q000235:genetics* / Q000276:immunology*; D011487:Protein Conformation; D060888:Real-Time Polymerase Chain Reaction; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014733:Vibrio / Q000276:immunology*
chemical_list: D018076:DNA, Complementary; D000075370:Receptors for Activated C Kinase; D011956:Receptors, Cell Surface; D002104:Cadmium