Genetic Variation And Tissue Expression Profile Study Of Cattle ACTL8 Genein

Actin-like protein 8（actin-like 8, ACTL8） is an important member of actin family. It is not only involved in cell division, cell motility, information transfer etc., but also provided with an inner endocytosis, cell morphology and polarity of the maintenance many functions.ACTL8 with microtubules and intermediate filaments（IF） constitute the cytoskeleton together.ACTL8 gene has the function of cytoskeleton protein to regulate and stabilize the muscle contraction, and it is related to the maturity and tenderness of meat. However, the correlation between ACTL8 gene and the growth with development of China cattle, as well as the mechanism of action is not clear in the muscle of cattle, still need further research. Therefore,on the basis of the cattle ACTL8 gene as the object of this study, research the ACTL8 gene genetic variation function. At the same time to analysis expression of ACTL8 gene in Qinchuan cattle at different ages in different tissue. In order to get the corresponding molecular genetics information, find the significant effect of molecular marker on the growth and development of China cattle. In- depth study of the ACTL8 gene in cattle muscle growth and development function to provide experimental basis, for China cattle genetic resources protection, development and use to provide genetic basis. The main research work and conclusions of this paper are as follows:1. Genetic polymorphism of cattle ACTL8 geneBy using PCR-RFLP and DNA pool sequencing technology to detect single nucleotide polymorphisms of cattle ACTL8 gene in Qinchuan 394, Xia’nan 213, Jinnan 180, Jia’xian 82,Nan’yang 81, De’nan 44. The result detected 5 mutations and 2 insert loss located in AC₀00159.1: c.2 135418240 A>G（SNP 1）, AC₀00159.1: c.2: 135553890 G>A（SNP 4）,AC₀00159.1: c.2 135552895 G>A（SNP 5）, AC₀00159.1: c.2 135416770 G>C（SNP 7）,AC₀00159.1: c.2 135415955 G>A（SNP 8） and rs714871276（SNP 11） deletion 17 bp base,rs714529542（SNP 12） insert 16 bp base, 135552895 G > A mutation loci were synonymous mutations [CTG（162 Leu） >CTA（162 Leu）].2. Analysis of cattle ACTL8 gene population genetics polymorphism lociBy χ2 test and linkage disequilibrium analysis, found that the SNP 1, SNP 4, SNP 5,SNP 11 and SNP 12 were consistent with Hardy Weinberg equilibrium, and the mutation loci of the polymorphism information content about 30%, it belongs to moderate polymorphisms（0.25 < PIC < 0.50）. It showed that the genetic properties of the 5 SNPs loci were relatively stable, and could be used as genetic marker and theoretical basis for cattle breeding. Whereas SNP 7 and SNP 8 are not in Weinberg Hardy equilibrium, the two mutations in this study population, which may be caused by inbreeding or migration or selection.The D’ value of SNP1 and SNP 4 in Xia’nan cattle was 0.988, SNP 4 and SNP 5 in Jia’xian cattle was 0.825, it indicated that there is a high degree of linkage disequilibrium between them（0.7 < D ’）.3. Correlation analysis of cattle ACTL8 gene polymorphism loci and growth traitsThrough correlation analysis found that SNP 1 with Qinchuan cattle, De’nan cattle, 24months- Nan’yang cattle were significantly associated with growth traits chest. SNP 4 with Xia’nan cattle, De’nan cattle, Jin’nan cattle were significantly associated with body height,and high at hip cross. Allele G was the advantages of six cattle breeds growth traits in SNP 4.SNP 5 with Jia’xian cattle, De’nan cattle were significantly associated with body length. SNP7 and SNP 8 were significantly associated with body length, chest circumference, long tajiri,and body height etc. in Qinchuan cattle. And the two SNPs loci in the advantages of Qinchuan cattle growth traits was allele G. SNP 11 with Xia’nan cattle, Jia’xian cattle were significantly associated with high at hip cross. SNP 12 with Xia’nan cattle, Jia’xian cattle, De’nan cattle were significantly associated with high at hip cross and chest girth. The results showed that the SNPs could be used as molecular marker for the improvement and selection of the growth traits of cattle.4. Analysis of tissue expression profile in Qinchuan ACTL8 geneUsing qRT-PCR technology to study the difference on the tissue expression profile of Qinchuan ACTL8 gene between three periods and seven groups. Relative quantitative results showed that its expression was influenced by specificity of time and space. In heart, liver,spleen, lung, kidney, muscle and fat of the Qinchuan fetal cattle, calves and adult cattle were detected expressions of ACTL8 gene. Compare the expression of quantity among tissues at the same time in Qinchuan cattle ACTL8 gene. According to the results, expression abundance of heart and fat tissue was the highest; the expression of muscle was higher in fetal bovine and adult cattle. But expression of muscle in fetal calf was the lowest. Comparing the expression of quantity tissues with different periods in Qinchuan cattle ACTL8 gene, the results showed that the expression of ACTL8 gene was significantly affected by the developmental stages.Changes in the heart, spleen, lungs, and fat were particularly evident, express quantity increased along with the age increasing（ P<01.0）. Expression abundance of kidney and muscle tissue in calf ACTL8 gene was the highest, in the fetal bovine was the lowest. The results showed that as the growth of the age, expression of kidney, muscle tissues in Qinchuan cattle ACTL8 gene was decreased after increasing. And there was no significant difference inthe expression of calves and adult cattle（ P>05.0）. For the further research on the role of tissues development in cattle ACTL8 gene will provide some basic information.