The microRNA gene <i>bta-mir-2313</i> in cattle: an atlas of regulatory elements and an association analysis with growth and carcass traits in the Slovenian Simental cattle breed

<p>MicroRNAs (miRNA) are a class of non-coding RNAs important in posttranscriptional regulation of target genes. Regulation requires complementarity between the target mRNA and the miRNA region responsible for their recognition and binding, also called the seed region. Previous studies have proven that expression profiles and genetic variations of miRNA genes (miR-SNP; SNP – single nucleotide polymorphism) and their target sites (miR-TS-SNPs) have an impact on phenotypic variation and disease susceptibility in human, animal models, and livestock. MicroRNA-associated polymorphisms therefore represent biomarker potential for phenotypic traits in livestock. Effects of miRNA gene polymorphisms on phenotypic traits have been studied in several animal species but much less in cattle. The aim of the present study was therefore to analyze the genetic variability in the <i>bta-mir-2313</i> gene and test associations with growth and carcass traits of the Slovenian Simmental cattle breed. Additionally, validated and predicted genomic information related to the miRNA gene <i>bta-mir-2313</i> has been obtained and presented as an atlas of miRNA regulatory elements. Sanger sequencing has been used for biomarker development and genotyping of 145 animals of Slovenian dual-purpose Simmental cattle. Out of nine known polymorphisms located within pre-miRNA regions, one mature miRNA seed SNP was polymorphic in the Slovenian Simmental cattle breed. An additional three polymorphisms were identified within the flanking pri-miRNA regions. There was no significant effect of polymorphisms on 18 tested fattening and carcass traits; however, validated polymorphisms could now be tested in association with other traits in other cattle populations. The microRNA gene <i>bta-mir-2313</i> warrants further genetic and functional analyses since it overlaps with a large number of quantitative trait loci (QTL), has over 3100 predicted targets and highly polymorphic mature seed regions, and is located within protein-coding gene <i>GRAMD1B</i>, previously associated with production traits in cattle. Mature miRNA seed SNPs present important genomic loci for functional studies because they could affect the gain/loss of downstream targets and should be systematically studied in cattle.</p>