[The cloning and expression analysis of Sox9b in Cyprinus carpio]

Sox9 gene is one of the important transcription factors involved in developments of many tissues and organs, particularly in sex determination and chondrogenesis. In this article, the genomic DNA of Cyprinus carpio were amplified using degenerate primers. It was found for the first time that there were two versions of Sox9 in C. carpio, Sox9a and Sox9b with the same deduced amino acid sequences in the HMG box. There is one intron in this box with the length 704bp in Sox9a and 616bp in Sox9b respectively. Furthermore, a two-phase rapid amplification of cDNA ends(RACE) was used for the isolation of the full length cDNA of Sox9b. Sequence analysis revealed a 2447bp cDNA encoding a protein of 428 amino acid. HMG box of 79-amino-acid motif was confirmed to be from 96 to 174. Sequence alignment exhibited the identity rate of amino acid of Sox9b among ten kinds of animals including C. carpio, which is above 75%. The result indicated the Sox9 gene is very conservative in the progress of evolution. The tissue-specific expression of Sox9b was studied with semi-quantity RT-PCR. The result showed that this gene expresses widespread in several organs of adult C. carpio, with the level of expression in brain and testis higher than any others.