cDNA cloning and characterization of a new member of the tumor necrosis factor receptor family gene from scallop, Chlamys farreri.
Tumor necrosis factors receptor (TNFR) is a superfamily of proteins derived mainly from vertebrates. It plays significant role in diverse physiological and pathological events such as inflammation, apoptosis, autoimmunity and organogenesis. The gene of a new member of TNFR family, designated as CfTNFR2, was cloned and characterized from scallop, Chlamys farreri. The full-length cDNA of CfTNFR2 consisted of 1,501 nucleotides with a poly (A) tail, encoding a polypeptide of 378 amino acids with the estimated molecular mass of 42.70 kDa and predicted isoelectric point of 4.79. The characteristic motifs of the TNFR family proteins, such as three TNFR homology domains (also called CRD domains) and a death domain, were identified in CfTNFR2. Significantly, the deduced amino acid sequence of CfTNFR2 was closely homologous with mammalian osteoprotegerins showing approximately 37% identity. However, it shared only 11% amino acids identity with CfTNFR1, another TNFR homolog previously identified from the candidate scallop species, indicating that CfTNFR2 is a new molluscan TNFR protein. The spatial expression of CfTNFR2 in the tissues of the healthy and bacterial challenged scallops was detected by real-time PCR. CfTNFR2 mRNA was expressed constitutively in all selected tissues such as mantle, gill, gonad, hepatopancreas and hemocyte, among which gill and mantle displayed comparatively higher expression levels. Upon Listonella anguillarum challenge, CfTNFR2 expression was found to be remarkably up-regulated, especially in the tissues of gill (15.9-fold) and mantle (8.0-fold). The results reveal that CfTNFR2 is a constitutive and inducible acute-phase protein apparently involved in immune defense. The presence of CfTNFR2 (present study) and CfTNFR1 (previously identified from our lab) encouraged us to suggest that multiple members of TNFR family exist in mollusk, and the findings would help us to get better understanding on the evolutionary origin and functions of this protein family in mollusks.
The Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
Jianguo
J
Su
Limei
L
Qiu
Ling
L
Li
Lin
L
Liu
Lingling
L
Wang
Vinu S
VS
Siva
Dahui
D
Yu
Linsheng
L
Song
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics*; D009928:Organ Specificity / Q000235:genetics; D049897:Pectinidae / Q000235:genetics*; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D012333:RNA, Messenger; D018124:Receptors, Tumor Necrosis Factor