Isolation, Characterization And Expression Analysis Of Bovine Micro RNA

Bovine is not only with important economic value but also with meaningful biological value. More and more evidence show that micro RNAs(mi RNAs) play important roles on the growth and development of animals. Mi RNAs are a class of endogenously small noncodings RNAs that are about 22 nucleotides(nt) in length. They are widely distributed in plants, animals and virus. It can make the target m RNA degradated or inhibit its translation by the way of complementary pairing with the 3’UTR region of target gene m RNA.The research of bovine mi RNA is lagging behind. This study collected multiple tissues of three developmental stages: 3-month-old fetus, 6-month-old fetus, 12-month-old Simmental Beef. And then construct 3 c DNA libraies acrroding to the 3 developmental stages. The 3 libraries were separately subjected to Solexa deep sequencing. We used the mi RDeep2 to analyze the sequence data. Meanwhile, we randomly selected and validated 9 mi RNAs in the 3 developmental stages of the expression profiles by stem-loop RT-PCR. The main results were as follows:Three libraries of different developmental stages were construct. The number of raw reads in 3 libraries are 24665837, 19963158, 20286502. After quality control, we obtained high-qu ality reads of 3 libraries stages were 23619093, 18746297, 18455215.The length of Small RNA sequence obtained from three libraries were mainly the 20~24nt, and peaked at 22 nt. The Unique Reads of 3 libraries were distributed in all chromosomes of bovine. The three libraries respectively obtained 696, 646, 605 mi RNAs, the number of the known mi RNA in an amount of 449, 435, 430 respectively by using mi RDeep2 program sequencing analysis.The tissue expression profiling of nine mi RNAs were detected by stem-loop RT-q PCR. The bta-mi R-1, bta-mi R-133, bta-mi R-206 has specific expression in the longissimus muscle and cardiac muscle, bta-mi R-378 is specific expresed in the longgissimus muscle, bta-mi R-338, bta-mi R-421, bta-mi R-2453, Novel_mi R-381, Novel_mi R-86 have different expression level in various tissues of 3-month-old fetus and expressed only in individual tissues of 6 months fetus and 12-month-old Simmental beef.By high-throuhghtput sequencing and bioinformatics analysis of three c DNA libraries, our study found a large number of bovine mi RNA sequences and identified some mi RNA’s expression profile. The results laid the theoretical foundation for the subsequent bovine genomics research.