Vitellogenin of Fujian oyster, Crassostrea angulata: Synthesized in the ovary and controlled by estradiol-17β.
In this study, we cloned a full-length cDNA encoding vitellogenin (Vg) in the Fujian oyster Crassostrea angulata. The complete Vg cDNA consists of 5160 nucleotides with a long open reading frame encoding 1641 amino acid residues. The deduced amino acid sequence shared high similarity with the Vgs of other mollusc, fish, nematode and arthropod species, particularly in the N-terminal region. We analyzed the spatiotemporal expression of caVg transcripts by Real-time Quantitative PCR. In common with other mollusc Vgs, the caVg gene was expressed primarily in the ovary, and the levels were 348 and 177 times higher in maturation and ripeness stages (P<0.01), respectively, than in the partially spent stage. There was negligible expression in male oysters. In situ hybridization analysis further localized caVg mRNA to the follicle cells (also named auxiliary cells) surrounding the oocytes in the ovary. Moreover, in vivo waterborne exposure experiments in early gametogenesis oysters showed that estradiol-17β (E2) administration resulted in a significant increase in caVg mRNA expression. We conclude that caVg is synthesized in the follicle cell surrounding the vitellogenic oocyte in C. angulata, and directly passed to oocytes through the extracellular space without mediation through hemolymph. Also, we hypothesize that this process is mediated by E2 in a dose dependent.
State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China; National Marine Hazard Mitigation Service, Beijing 100194, China.
Jianbin
J
Ni
State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China.
Zhen
Z
Zeng
State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China.
Dezheng
D
Kong
State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China.
Lin
L
Hou
School of Life Sciences, Xiamen University, Xiamen 361005, China.
Heqing
H
Huang
State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361005, China. Electronic address: chke@xmu.edu.cn.
Caihuan
C
Ke
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D049896:Crassostrea / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics; D004958:Estradiol / Q000378:metabolism* / Q000494:pharmacology; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D006080:Ovarian Follicle / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010053:Ovary / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012098:Reproduction / Q000235:genetics; D013737:Testis / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors; D014819:Vitellogenins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics
D018076:DNA, Complementary; D012333:RNA, Messenger; D014819:Vitellogenins; D004958:Estradiol
Crassostrea angulata; Estradiol-17β; Follicle cell; Oyster; Vitellogenin gene