Molecular cloning of the alpha subunit of complement component C8 (CpC8α) of whitespotted bamboo shark (Chiloscyllium plagiosum).
Complement-mediated cytolysis is the important effect of immune response, which results from the assembly of terminal complement components (C5b-9). Among them, α subunit of C8 (C8α) is the first protein that traverses the lipid bilayer, and then initiates the recruitment of C9 molecules to form pore on target membranes. In this article, a full-length cDNA of C8α (CpC8α) is identified from the whitespotted bamboo shark (Chiloscyllium plagiosum) by RACE. The CpC8α cDNA is 2183 bp in length, encoding a protein of 591 amino acids. The deduced CpC8α exhibits 89%, 49% and 44% identity with nurse shark, frog and human orthologs, respectively. Sequence alignment indicates that the C8α is well conserved during the evolution process from sharks to mammals, with the same modular architecture as well as the identical cysteine composition in the mature protein. Phylogenetic analysis places CpC8α and nurse shark C8α in cartilaginous fish clade, in parallel with the teleost taxa, to form the C8α cluster with higher vertebrates. Hydrophobicity analysis also indicates a similar hydrophobicity of CpC8α to mammals. Finally, expression analysis revealed CpC8α transcripts were constitutively highly expressed in shark liver, with much less expression in other tissues. The well conserved structure and properties suggests an analogous function of CpC8α to mammalian C8α, though it remains to be confirmed by further study.
The State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China; School of Life Science and Technology, China Pharmaceutical University, Nanjing 210009, PR China.
Ying
Y
Wang
Mengmeng
M
Zhang
Conghui
C
Wang
Boping
B
Ye
Zichun
Z
Hua
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002681:China; D003001:Cloning, Molecular; D003185:Complement C8 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment; D012754:Sharks / Q000235:genetics* / Q000276:immunology*
D003185:Complement C8; D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger
C8 alpha subunit C8α; Cartilaginous fish; Chiloscyllium plagiosum; CpC8α; EGF; GSP; LD PCR; LDLRA; MAC; MAC/perforin domain; MACPF; RACE; Shark complement; TCCs; TSP1; The membrane attack complex (MAC); UTRs; epidermal growth factor (EGF)-like domain; gene-specific primers; long distance PCR; low-density lipoprotein receptor class A; qRT-PCR; rapid amplification of cDNA ends; real-time quantitative RT-PCR; the membrane attack complex; the terminal complement components; thrombospondin type 1; untranslated regions; α subunit of complement component C8 in Chiloscyllium plagiosum