Homology, Polymorphism Analysis And Expression Levels In Different Stages Of MITF Gene In Rabbit

The exon2, exon4, exon5and exon7of MITF gene in rabbit was cloned in this experiment, and compared the sequence’s homology with human, horses, bovine, rat, chicken and so on several species. The results showed that these segments had highly homology in different mammals, more than90%, and the homology with poultry was lower, over84%, and improved that this gene was relatively conservative in the species evolution process.In this experiment, we designed primers, and adopted PCR-SSCP technology to detect the polymorphisms of part sequences of MITF gene which contained five exons, taking white rex rabbit、Beaver rex rabbit、Minxinan black rabbit、Jiuyishan rabbit and Belgian rabbit populations for experimenting. The results showed that, the product of primer1,2,5and7didn’t performe polymorphism, and there was a SNP point (C43T) in the255bp product of primer4, which represented AA, AB and BB genotypes in all populations. The sequencing results indicated that the base transition was located in5’intron region, and the effect on the amino acid sequences encoding of MITF gene was remained to confirm. The statistical results showed that, all the populations were in Hardy-Weinberg equilibrium except white rex rabbit and Jiuyishan rabbit(P<0.05). Minxinan black rabbit and Belgian rabbit performed moderate polymorphisms (0.5>PIC>0.25), and the other populations were low polymorphisms.In the study of MITF gene expression rules in rabbit, we collected the back skin tissue from the offspring group of Fujian yellow rabbit and New Zealand white rabbit, at the4,6,8,10and12weeks of age. Then using fluorescence quantitative PCR technology, to determine the mRNA relative expression levels of MITF gene in various periods, and analyze the mRNA expression rules of MITF gene in this growth stage. The results showed that the expression of male and female rabbits appeared a rapid growth from the4th week, and reached a peak at the 6th week, then turned to decrease. It reflected that, with the arrival of moult, the MITF gene became activity. After the8th week, male and female rabbit began to show different variation trends, the female turned into the second fluctuations, meanwhile the male growed steadly. Combinating with physiological difference of sex, maybe the different levels of estrogen lead to the different variation trends. The variation trends indicated the expression of MITF gene may be effected with hair follicles growth cycle and estrogen level, and MITF gene was concerned with the regulation for the formation and changing of coat color in a certain degree, and may be a important gene on effecting hair color. In addition, in the analysis of expression difference between normal color and black macula skins, the expression of MITF gene in black macula was distinctively higher than in normal skin, as well, validated MITF gene’s expressing may be related to the melanin’s formation and accumulation, and then effect the color of skin and hair.