Polymorphism and parent-of-origin effects on in vitro cellular differentiation, expression and epigenetics in genes of economical importance in beef cattle

Abstract

In this work, we aim to evaluate polymorphism and allelic parent-of-origin effect on in vitro cellular differentiation, gene expression and epigenetic modifications in genes involved in traits of economic importance for beef cattle, including tenderness, marbling and subcutaneous backfat deposition. For that purpose, pregnant uteri will be obtained in slaughterhouse and samples of maternal uterus and fetal skin tissues will be collected and used for genotyping mother and fetus. In these animals, single nucleotide polymorphisms (SNP) will be assessed in coding regions of calpain, calpastatin, DGAT1, and leptin genes. Afterwards, myoblast and adipocyte precursor cells collected respectively from muscle and adipose tissue of homozygous and heterozygous fetus whose mother is homozygous for those SNP will be submitted to in vitro culture and evaluated after induced differentiation. In those tissues, gene expression will also be assessed before culture, after differentiation and after treatment with epigenetic modifying agents. In muscle, adipose tissue, and liver of the heterozygous fetus, the expressed allele and its parental (maternal or paternal) origin will be determined using allelic discrimination in real time PCR. For the gene with higher tissue-specific, allele-preferential or parental-origin differential expression, the technique of chromatin immunoprecipitation (ChIP) will be employed to assess the epigenetic mechanisms possible involved. ChIP will be performed using antibodies for methylated DNA and for histones modified by acetylation and methylation. Thus, the objective is to comprehend epigenetic mechanisms controlling the expression of genes of economic importance for beef cattle, and then allowing the development of ways to modify it and establishing new criteria to be used for marker assisted selection, aiming to improve carcass traits and meat quality. (AU)