Cloning Gonald-inhibiting Hormone Gene In Eriocheir Sinensis

Chinese mitten crab (Eriocheir sinensis) is an important economic crab, as one of the famous freshwater species for aquaculture. It exists throughout South and North of freshwater in China. But sexual premature in larvae occurred widespread and influenced the yield badly. The majority of scholars believed that the external environment and theirselves's regulation of reproductive endocrine plaied a common role on the sexual premature of the crab, in which gonad-inhibiting hormone was important on the regulation of the gonadal maturation.At present, There were two main methods on the sexual premature of crustacean research: One is on embryonic development, larval morphology and histology and cytology of the study; The other is to use molecular biology methods to research gonad-inhibiting hormone in genetic levels. Now, there were five specieses of shrimp gonad-inhibiting hormone were sequenced, and no crab sequence reported.In this paper, genetic engineering technique was used for studying on gonad-inhibiting hormone(GIH), which has an important effect on chinese mitten crab gonad growth. The 16 pairs primers designed according as known conservative and codon usage of gene sequences gonad-inhibiting hormone, and homologous tree of chinese mitten crab.During the experiment, optic ganglion of chinese mitten crab was dissected fristly. Then total RNA was extracted by using the TRIzol reagent. Three DNA fragments were obtained after PCR, cloned and sequenced. The results showed these DNA fragments were similar to the known GIH in 38%-43%. By blasting in Swiss-Prot database there were EGF-like domain signature,2Fe-2S ferredoxin-type iron-sulfur binding region signature and C-terminal cysteine knot domain signature in the DNA fragments as all GIH. So the DNA fragments were presumed to GIH-like fragments of chinese mitten crab.