Effects of new polymorphisms in the bovine myocyte enhancer factor 2D (MEF2D) gene on the expression rates of the longissimus dorsi muscle

E Juszczuk-Kubiak,K Wicińska,T Sakowski,R R Starzyński,K Flisikowski

doi:10.1007/s11033-012-1689-6

Abstract

Myocyte enhancer factor 2D (MEF2D), a product of the MEF2D gene, belongs to the myocyte enhancer factor 2 (MEF2) protein family which is involved in vertebrate skeletal muscle development and differentiation during myogenesis. The aim of the present study was to search for polymorphisms in the bovine MEF2D gene and to analyze their effect on MEF2D mRNA and on protein expression levels in the longissimus dorsi muscle of Polish Holstein–Friesian cattle. Overall, three novel variations, namely, insertion/deletion g.−818_−814AGCCG and g.−211C<A transversion in the promoter region as well as g.7C<T transition in the 5′untranslated region (5′UTR), were identified by DNA sequencing. A total, 375 unrelated bulls belonging to six different cattle breeds were genotyped, and three combined genotypes (Ins-C-C/Ins-C-C, Del-A-T/Del-A-T and Ins-C-C/Del-A-T) were determined. The frequency of the combined genotype Ins-C-C/Ins-C-C and Del-A-T/Del-A-T was varied between the breeds and the average frequency was 0.521 and 0.037, respectively. Expression analysis showed that the MEF2D variants were highly correlated with MEF2D mRNA and protein levels in the longissimus dorsi muscle of Polish Holstein–Friesian bulls carrying the three different combined genotypes. The highest MEF2D mRNA and protein levels were estimated in the muscle of bulls with the Ins-C-C/Ins-C-C homozygous genotype as compared to the Del-A-T/Del-A-T homozygotes (P < 0.01) and Ins-C-C/Del-A-T heterozygotes (P < 0.05). A preliminary association study showed no significant differences in the carcass quality traits between bulls with various MEF2D combined genotypes in the investigated population of Polish Holstein–Friesian cattle.Electronic supplementary materialThe online version of this article (doi:10.1007/s11033-012-1689-6) contains supplementary material, which is available to authorized users.

Highlights

The myocyte enhancer factor 2 (MEF2) transcription factors family has been shown to play a crucial role in the activation of muscle-specific gene transcription in skeletal, cardiac, and smooth muscle cells [1]
Members of the MEF2 family of transcription factors are up-regulated during skeletal muscle differentiation and cooperate with the MyoD family of myogenic basic helixloop-helix transcription factors to control the expression of muscle-specific genes [1, 2]
Several studies have clearly shown that MEF2 factors are involved in the postnatal regulation of skeletal muscle development, growth and homeostasis [8, 14]

Summary

Introduction

The myocyte enhancer factor 2 (MEF2) transcription factors family has been shown to play a crucial role in the activation of muscle-specific gene transcription in skeletal, cardiac, and smooth muscle cells [1]. Zhao et al [8] confirmed that MRF and MEF2 families are crucial for the phenotypic differences between two pig breeds and proposed a novel model of myogenesis. According to these authors, MyoD and MEF2A control the balance between intermuscular adiopogenesis and myogenesis by regulating CCAAT/enhancer-binding protein (C/EBP) family, while MEF2C and myogenic factor 5 (Myf5) are important during the whole myogenesis process and MEF2D affects muscle growth and maturation

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