The Gene Expression Of MIH And FAMeT In The Ovarian Development Of Portunus Trituberculatus

To study the regulatory role of Farnesoic acid O-methyl transferase (FAMeT) and moltinhibiting hormone (MIH) in the ovarian development and molting process of crustaceans, the full-length FAMeT cDNA (GenBank accession number: KC192659) of P. trituberculatus is firstlycloned by using reverse transcript PCR (RT-PCR) and rapid-amplification of cDNA ends (RACE),FAMeT cDNA contains a201bp5’-untranslated region(5’-UTR), a318bp3’-untranslated region(3’-UTR) and a825bp opening reading frame, which encodes274amino acid residues. Alignmentof deduced amino acid sequence with FAMeT amino acid sequences of other crustaceans revealedthat it shares the highest identity with P. Pelagicus among the identities ranged from75%to97%.The amino acid residues consist of two copies of CF (CPAMD8/FAMeT) domain, which are thehallmark domain of FAMeT and are present in all crustacean FAMeTs. The tissues expressionrsults showed that FAMeT was expressed in various tissues, and highest in thoracic ganglia.During the molting process, the expression of FAMeT in MO increased to the maximum at D1stage, then gradually decreased to the minimum at D4stage. These results suggest that FAMeTplays an important role on physiological regulation in P. trituberculatus.qRT-PCR was used to quantify the relative expression of Vg, FAMeT and MIH in differentovarian development stages of P. trituberculatus. The mRNA levels of Vg in the ovary was low instage I and II, than rapidly increased in stage III, to the maximum in stage IV; after ovulation, itcame back to a low level. The change of Vg mRNA level in the hepatopancreas was similar to thatin ovary, besides the sequentially increasing in stage V. During the ovarian development, theexpression of FAMeT was highest in MO at stage II, FAMet gene expression increased graduallyfrom stage III to stage V.The MIH gene expression in the ovarian development was highest instage I, then gradually decreased, to the minimum at stage IV and V, after ovulation, it came backto a high level. These results suggest that the gene expression level of MIH in closely related to theovarian development, it may inhibit the ovarian development.