Identification of microRNA in fresh milk of cow and goat

Abstract Text: MicroRNAs (miRNAs) are a class of small RNA molecules (~22 nt) that inhibit translation or induce degradation of protein-coding mRNAs containing complementary sequences to mRNAs. Recent studies have demonstrated the presence of miRNAs in body fluids such as serum, plasma, saliva, urine and milk. The objective of this study was to identify the differences of microRNA profiles between cow whey and goat whey. Cow whey samples and goat whey samples without milk fat, somatic cells and major proteins were obtained by a series of centrifugations and filtrations. miRNA was isolated and the quantity of RNA measured. Isolated miRNAs were amplified and sequenced by Solexa sequencing technology. After bioinformatics analysis, 381 loci possessed the typical stem-loop structures matched to the known miRNA hairpins and a total of 34 loci with novel hairpins were identified as novel miRNAs in cow whey. In goat whey, a total of 111 microRNAs were obtained of which 13 were novel microRNAs. Among all the microRNAs detected in cow and goat whey, 29 miRNAs were common between these species. Overall, the miRNA profile of cow whey and goat whey differed significantly.

Keywords: fresh milk, whey, microRNA