Isolation, Polymorphism, Expressionof CCTF And The Expression Difference Between Cyprinus Carpio Var. Jian And C. Var. Wuyuanensis

Transferrin (Transferrin, Tf), is a very important ?-globulin and plays an important role in the iron metabolism and participates in the immune response. Here, we cloned two CcTf cDNA sequences from Cyprinus carpio var. jian and C. var. Wuyuanensis. Two open reading frame (ORF) sequences were 2010bp and 2013bp, coding 669 and 670 amino acids, respectively. Both of them contained one signal peptide and two characteristic domains of transferrin protein family. The NJ tree showed that the evolutionary relationships of Tf was almost the same as the traditional morphological and biochemical characteristics classification, and clustered into two branches, fish and other vertebrates. In fish branch, Perciformes as Larimichthys crocea, Dicentrarchus, Oreochromis went together with Salmoniformes as Salmo salar, Oncorhynchus, mykiss and Pleuronectiformes as Paralichthys olivaceus and Siluriformes as Tachysurus fulvidraco first, and then converged with Cyprinidae as Danio rerio, Ctenopharyngodon idella, Hypophthalmichthys molitrix and Cyprinus carpio. Both CcTfs had 17 exons and 16 introns but obvious variances were found in the length and sequence between introns. Total 32 polymophic loci were observed at CcTfs through comparing sequences. Polymorphic locus at intron 4 of CcTf-2 in C. var. Wuyuanensis had two genotypes while C. var. Jian just had only one.The real-time quantitative PCR results showed that the CcTfs expressed in brain, heart, liver, kidney, intestine, muscle, testicle and ovary, and highest level was observed in liver. The comparison of transcriptome between C.var.jian and Cvar. wuyuanensis which had different muscular fatty acids composition showed the expression level of Tf was significantly different. In order to confirm the correlation between levels of Tf and fatty acids contents, we detected the expression of CcTfs in muscle and liver including C. carpio var. jian and C. carpio var. Wuyuanensis cultivated under the same conditions. Results indicated that there was no significant difference between liver expression levels, while, expression level of CcTfs was significantly higher in C. carpio var. wuyuanensis muscle than that in C. carpio var. Jian which consistent with transcriptome comparison results. However, further regression analysis displayed that no correlation between CcTfs levels and muscular fatty acids, serum lipoproteins, respectively.The experiment results indicated that the genome of C. carpio existed two CcTfs genes with highly similarity in ORF and significant difference in the introns, which indicated chromosome replicated event in formation of C. carpio. The phylogeny of Tf was consistent with the traditional classification. CcTfs had the highest expressional level in liver which was similar with other fishes. Significantly different expression levels of CcTfs were observed between Jian carp and red purse carp muscle, though there was no correlation between CcTfs levels and muscular fatty acids, serum lipoproteins.