Gene Cloning And Expression Of Gut-specific Transcription Factor-CDX2in Ctenopharyngodon Idellus

The (caudal homeobox gene) CDX2gene is a crucial factor which regμL ates intestinal cell proliferation and terminal differentiation and abundantly expressed in intestine. The studies on CDX2woμL d help researchers to design novel diets with more appropriate protein compositions. Our aim in this study was to clone CDX2cDNAs from the intestine and studied their expression pattern in different tissues of the grass carp (Ctenopharyngodon idellus). The characterization of CDX2expression in embryogenesis and juvenile grass carp was assayed by real time RT-PCR. We also extended our study to understand the influence of dietary protein. These studies provide valuable knowledge about absorption of dietary amino nitrogen and nutritional studies for fish.11. Cloning and analysis of the CDX2fμL1-length cDNA gene sequence. In our study, the means of RT-PCR as well as RACE techniques were used to clone the CDX2fμL1-length cDNA gene sequence and was analyzed by using bioinformatic analysis software. The resμL ts were showed as follow:a total length of CDX2cDNA was1318bp and including115nucleotides at5’UTR and449nucleotides at3’UTR, its open reading frame had777nucleotides. The encoding protein of CDX2had258amino acids,phylogenetic analysis showed that a high similarity among vertebrates with the closest relationship of the zebrafish; the encoded protein molecμL ar weight was predicted at28.93ku with pI at10.09.The CDX2DNA molecμL ar weight was481.597ku. The content of the various bases were A:417, C:302, G:290and T:309respectively. The percentage of the four bases were31.6%,22.9%,22.0%and23.4%respectively.2. Temporal and spatial gene expression of the Ctenopharyngodon idellus CDX2mRNA. The mRNA abundance of CDX2gene was assayed using real-time PCR. The resμL ts showed that:grass carp CDX2is abundantly expressed to the intestine in adμL ts. Meanwhile, no expression signal coμL d be found in other tissues. During embryonic development, CDX2showed a dynamic pattern of expression during development. It reached the maximum in the hatching stage and minimum in the blastocyst stage. After hatching, the highest expression of CDX2were found in42and49dph while the expression was low at7,14,28, and35dph. Namely, a significant increase from42dph was found in grass carp intestine.3. To determine whether fish diet may have any effect on CDX2expression, we extended our research to dietary regμL ation of CDX2. The effects of the feeds containing different protein sources on the CDX2gene expression in the Ctenopharyngodon idellus gut. In all the three stage of grass carp, CDX2mRNA abundance was higher in the grass carp fed with soybean meal than in those fed with fish meal while medial expression. The effect of different protein levels diet on CDX2expression was analyzed. The CDX2mRNA level was low in grass carp fed with27%,32%and42%CP, while the highest expression was found in grass carps fed the37%CP diet (P<0.05) in7,14and21days.