Evaluation of the Effects of Bovine Leukemia Virus MicroRNAs on the Expression Level of TET3 and MLL2 Genes

Bovine leukemia virus (BLV) usually infects B lymphocytes and expresses a cluster of ten microRNAs (miRNAs). The microRNAs produced by the virus in infected B lymphocytes usually constitute about 40% of all the miRNAs of the infected B-lymphocytes. The purpose of this study, bioinformatics investigation was done to identify the number of target genes of each of the BLV- miRNAs. Also, the evaluated of the expression level miRNA-B4-3p, B2-5p, and their target genes TET3, MLL2.

Each miRNA-BLV sequence was obtained from the miRBase sequence database and was then assessed by TargetScan and miRWalk software to investigate the target genes of each miRNA of the virus. In the experimental phase of the study, the infected animals were divided into two groups based on the two forms of BLV+ infection; PL form compared with AL form (Group 1) and BLV+ with normal lymph nodes compared with lymphosarcoma form (Group 2). RNA extraction was performed and cDNA synthesized for genes. qPCR was used to evaluate the expression levels of the miRNA and target genes. The expression levels of two miRNA B4-3p, B2-5p, and two genes TET3, MLL2 in two groups were compared.

The Fold Change (FC) values for B4-3p and B2-5p in group 1 were 22 and 67, respectively. In group 2 for B4-3p and B2-5p were 47 and 133, respectively. But there was no change in the expression level of these two gent MLL2 and TET3 in the two groups.

Despite a significant increase in expression level in B4-3p, B2-5p. there was no significant difference in MLL2 and TET3 expression in group 1and 2.