| Due to people's lack of understanding the molluscs endocrine system, This has been a controversial issue that whether steroid hormones have the same functions in mollusks as they have in higher animals, especially in mammals where steroid hormones make a function as the semiochemicals in endocrine system.17-beta-hydroxysteroid dehydrogenase family in the higher animals endocrine system plays a key role, it mainly catalyzes the transformation between estrone and estradiol androstenedione and testosterone, as a result controlling the balance of non-active and active of the principal hormone in vivo. The different member of the family primarily makes a responsible for one reaction in one direction.Through construction of cDNA library of abalone and anchored PCR after reverse transcription of tissue mRNA we obtain a nucleotide sequence including a complete open reading frame and corresponding peptide sequence. By a large number of bioinformatic analysis and comparison of the sequence we found the highest structural similarity between it and the 17-beta-hydroxysteroid dehydrogenase12 in higher animals. Through construction expression vector in cell before it is transfected into 293t cell and detection of substrate specificity of the enzyme after using estrone (E1) and estradiol (E2) as the substrate separately, we found the enzyme has a high activity of converting estrone into estradiol, but cannot convert estradiol into estrone. Through using real time quantitative PCR (RT-PCR) to detect changes in tissue distribution and expression of the sequence, we found that the expression change is one decreasing by one increasing from before spawning to after it in gonads and hepatopancreas and there has a higher expression in gonads than hepatopancreas The experimental result suggest that there has the key enzyme–the member of 17-beta-hydroxysteroid dehydrogenase family similar to that in higher animals endocrine system and it take part in the processing of steroid hormone in abalone. |
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