Clonal Analysis, Genetic Variants Of MC1R Gene And Dynamic Expression In Rabbit

Mammalian animals had many types of coats, mainly caused by the different distribution of melanin by melanocytes.The fur color of rabbit was not only the mark of the varieties, but also had important economic value.MC1R (melanocortin1-receptor) gene, also called melanin cortical hormone receptor1, was existented in mammalian melanoma cells. Colored hair phenotype of the mammalian was regulated by the different alleles of melanin cortisol receptor1point. MC1R was a unique, dual-function control receptor. The MC1R gene was a member of the G protein-coupled receptor family, encoded by the extension locus and formed about310amino acids. MC1R gene had only one exon, seven transmembrane domains, and was the smallest G-protein coupled receptors. In mammals, MC1R had an important regulatory role for melanin formation, so it was direct relationship between genes found so far.In this experiment, four varieties of rabbits were detected as experimental animals, PCR-SSCP technique for polymorphism analysis. Rabbit MC1R gene exon were cloned and sequenced, got the nucleotide sequence of exon,camparied with other species MC1R nucleotide sequences published in the NCBI database. The results were showed as follows:1. According to sequences of Papio Anubis published in GenBank, designed primers, got the nucleotide sequences of MC1R in rabbit and compared these nucleotide sequences with other animals. Constructed the evolutionary tree among rabbit and other species by molecular systems.The results showed that, the exon length of MC1R gene was924bp. Compared with people,baboons were88.3%and88.7%; Compared with pigs and cattle were88.1%and87.4%; Compared with rat and mice were83.4%and86.1%. Translated nucleotide sequences into amino acids, and forecasted the information of rotein:the number of A, T, C and G base were 232,225,237,230; alpha helix42.3%, random coil37.5%, turn11.3%; prediction of amino acid residues covering4hydrophilic regions and3hydrophobic regions.2. In MinXi’nan Black Rabbit, Chinchilla Rabbit, White Rabbit and Jiuyi mountain rabbit species, single nucleotide polymorphisms was used to analysis MCIR gene, and found two alleles, three genotypes;103-108was inserted with a AGACGG. Heterozygosity of the four varieties was between0.140-0.251, polymorphism information content was around0.20. Acorrding to the prediction secondary structure of protein, the insertion mutation made a little change on the conformation of protein occurs, it maybethe impacted the regulation of activity between different alleles of the gene.3. In this study, MCIR gene expressed a certain amount in different weeks. At the4th week age, RQ amount was in a low level, but during6-10weeks, it showed a rising trend, achieved to the peak at the10th week. During10-12weeks it performanced a downward trend, but still higher than8week age relative expression quantity. RQ did not show significant difference between the genders.