Genetic Effects And MRNA Expression Of ASB-3 Gene In Three Chinese Indigenous Cattle

ASB-3 is one of the 18 members of ASB gene family. As a special negative regulation factor of TNF-R2, ASB-3 inhibits the signal transduction of JNK-TNF-R2 and JNK-STAT signaling pathway by TNF-R2 protein. What’s more, JNK-STAT is a signal transduction pathway that is stimulated by cytokine, which involves in cell proliferation, differentiation,apoptosis and immune regulation, and many important biological processes. Therefore, ASB-3may have effects on animal immune regulation and the growth traits. In addition, whole genome sequencing of hybrids of Japanese black cattle and Angus confirmed that the effect of ASB-3 on the back fat growth was significant. Therefore, ASB-3 involves in the immune adjustment process and probably by regulating the expression of related functional genes,effect of intramuscular fat content and other traits of expression, which affect the growth and development of livestock, can be used as a candidate gene of cattle breeding research.However, at present, the expression of ASB-3 gene in different tissues and the effects of genetic variation on the growth and development of cattle are still very scarce. Therefore, this experiment is planed to study the expression differences of ASB-3 among tissues and its genetic variation and to analyse association between these variants and growth traits in Qinchuan cattle, Jinnan cattle and Xianan cattle, in order to find genetic marker that could be applied to cattle breeding. 1.Study on the genetic variation of ASB-3 geneUsing the sequencing of mixed DNA pool, Tetra-primer ARMS-PCR and PCR-RFLP,this study detected the genetic polymorphism of ASB-3 of Qinchuan, Jinnan and Xianan cattle.in total of 637 individuals. Four mutation sites were detected. More importantly, the g.C41255 T, g.G74754 A, and g.T75438 C were synonymous mutation, whereas the g.C115213 T was missense mutation(Pro 38405 Ser). Genetic diversity index(PIC, He and Ne) showed that these 4 polymorphic loci of ASB-3 gene were moderate polymorphism in most of populations. Because their polymorphism information is abundant, the breeding potential is great. Through the analysis of linkage disequilibrium between three cattle breeds show that only in Jinnan cattle there are strong linkage and the relationship in the SNP1 respectively with SNP3 and SNP4, and between the SNP3 and SNP4. Haplotype analysis found that the number and frequency of the haplotypes in different varieties were different.breedsThe four polymorphic locis of ASB-3 gene respectively with three breeds of cattle growth traits associated analysis found that: SNP1 site is significantly related with Qinchuan cattle height,TT as the dominant genotype; SNP2 has a significant relationship with Xianan cattle’s body length and Qinchuan cattle’s cross department height, AA as the dominant genotype; SNP3 is significantly related to Xianan cattle’s cross height, TT as the dominant genotype; SNP4 site is significantly correlated with Xianan cattle’s body height and Jinnan cattle’s cross height.. Genotype combinations are only significantly correlated with adult Qinchuan cattle hucklebone width. The combination genotype CTAGCTCC outperforms Qinchuan cattle other combinations of genotypes. The results show that the early selection for cattle breeds by selecting TT and AA advantage genotype3.Expression analysis of ASB-3 gene in Qinchuan cattle tissueUsing Real-time PCR, the gene ASB-3 expression level of Qinchuan cattle in different periods(fetal bovine and adult cattle) and different tissues(heart, liver, spleen, lung, kidney,intestine, fat and muscle) expression were detected. The results showed that ASB-3 gene in Qinchuan cattle fetal bovine was expressed in seven tissues except fat tissue of fetal cattle,whereas it expressed in eight tissues of adult cattle. The ASB-3 gene was widely expressed in Qinchuan fetal bovine tissues, and the difference between the expression of tissue in different periods. The expression of ASB-3 gene in liver and muscle tissue was significantly different between the two different growth stages.4.The impact of genetic variation on the expression of ASB-3 gene in Qinchuan CattleRespectively select 60 healthy Qinchuan cattle fetal bovine and twenty-six Qinchuan cattle adult cattle, take the muscular tissue and to each individual genotyping was performed using Tetra-primer ARMS-PCR technique, using real-time PCR was used to detect the ASB-3gene expression, and to analyze the difference of ASB-3 gene expression between different genotypes. In Qinchuan fetal bovine with SNP1 site, there are significant expression differences among genotype CT, CC and T; in the cattle with SNP4, the expression is significantly different in the individuals with genotype CT and CC. Although the expression differences in adult bovine with these genotypes were not significant, in SNP1, SNP2 and SNP4 locus, CT genotype expression were higher than the CC and TT genotypes The correlation analysis showed that these three loci for each genotype are consistent with body traits, concluding that SNP1 and SNP3 were positively related to Qinchuan cattle bust, chest deep, body width, whereas SNP4 had a negative regulation. The results showed that 3 SNP2.Correlation analysis of ASB-3 gene polymorphism and growth traits of three cattleloci were found in this study probably through the effect of DNA- RNA- phenotype, change the expression of the gene in muscle and its effect on the regulation of muscle or adipose tissue development, thus affecting the growth traits of cows.