The molecular characterization and temporal–spatial expression of myocyte enhancer factor 2 genes in the goat and their association with myofiber traits

Abstract

The myocyte enhancer factor-2 (MEF2) gene family in vertebrates includes MEF2A, MEF2B, MEF2C, and MEF2D, which have important functions in the regulation of muscular growth and development. To investigate their temporal–spatial expression and functions in the goat, these genes were cloned (accession nos. JN967621–24) and their expression patterns characterized at five postnatal stages (3, 30, 60, 90, and 120days). Association analysis was then applied regarding MEF2 expression levels and myofiber diameter and density. MEF2B was shown to be weakly homologous with other species, the distant branches with other members and the lowest expression levels, suggesting that it is distinct from other family members. Expression of the other three MEF2 genes was widely distributed, but this was largely accumulated in the skeletal muscle and myocardium compared with the viscera at all developmental stages. MEF2A and MEF2D expression levels were higher overall than MEF2B and MEF2C in six tissues, and were significantly positively correlated with the myofiber diameter of the longissimus dorsi. These findings suggest that goat MEF2 genes mainly function in the skeletal muscle and myocardium, and that MEF2A and MEF2D are likely to effectively promote muscular growth and development during postnatal stages. MEF2A expression was highest in the myocardium, where MEF2C expression increased with age, implying that both gene products are related to the growth and development of postnatal myocardium.