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Vitellogenesis in the red crab Charybdis feriatus : Hepatopancreas‐specific expression and farnesoic acid stimulation of vitellogenin gene expression
Author(s) -
Mak Abby Sin Chi,
Choi Chi Lung,
Tiu Shirley Hiu Kwan,
Hui Jerome Ho Lam,
He JianGuo,
Tobe Stephen S.,
Chan SiuMing
Publication year - 2005
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.20213
Subject(s) - vitellogenesis , vitellogenin , hepatopancreas , biology , complementary dna , microbiology and biotechnology , hemolymph , gene expression , gene , biochemistry , genetics , oocyte , embryo
Vitellogenesis in the mature female crab Charybdis feriatus occurs all year round during which active synthesis of the vitellogenin (Vg) precursor occurs. Several polypeptides from the ovaries were shown to be immuno‐reactive to the shrimp vitellin (Vn) antibody. N ‐terminal amino acid sequence determination revealed that several ovarian polypeptides and one polypeptide secreted by the hepatopancreas were identical to part of the C. feriatus Vg (CfVg) precursor. The full‐length cDNA sequence encoding a protein with high amino acid sequence similarity to the Vg of the shrimp Metapenaeus ensis was cloned. In common with the shrimp M. ensis MeVg2 , the crab vitellogenin gene is expressed only in the hepatopancreas. The expression level of CfVg is undetectable in the non‐reproductive females, increases to maximum at the middle stages of vitellogenesis and drops to a lower level in late vitellogenesis. Expression of CfVg also extended to females that are undergoing brooding of developing larvae. Although the 8 kb transcript for the full‐length cDNA was detected, smaller transcripts specific to CfVg mRNA were also detected, suggesting the occurrence of alternative splicing/expression of the CgVg gene to produce the smaller transcripts. Using a short term in vitro hepatopancreas explant culture assay, we have demonstrated that low concentrations of farnesoic acid (FA) stimulate CfVg gene expression in the hepatopancreas. Although both methyl farnesoate (MF) and juvenile hormone III also caused up‐regulation of the CfVg gene, their effects are only significant at much higher concentrations. Mol. Reprod. Dev. 70: 288–300, 2005. © 2005 Wiley‐Liss, Inc.