Identification Of MEF2C Gene Alternative Splicing And The Association Of Its Single Nucleotide Polymorphisms With Growth Traits In Goats

Myocyte Enhancer Factor 2C(MEF2C) belongs to MEF2 gene family which is a member of the MADS-Box transcriptional factors. MEF2C widely exists in myocardium, skeletal and smooth muscle, and plays an important role in muscle development by controlling the muscle cell differentiation in the process of gene transcription.Here, we used the Nanjiang yellow goat tissues to explore alternative splicing and quantified their expression in different periods of the myocardium and skeletal muscles by RT-qPCR, subsequently we also detected the polymorphisms of MEF2C exons, and the main results were as follows:(1) Three spliceosome of goat MEF2C gene, MEF2C-AS1, MEF2C-AS2 and MEF2C-AS3, were successfully cloned, their coding sequences were 1388 bp,1382 bp and 1244 bp, and encoded 433 aa,431 aa, and 433 aa, respectively. Exon 7 of MEF2C was completely absent in MEF2C-AS1; MEF2C-AS2 completely lacked exon 6; while both exons 6 and 7 were absent in MEF2C-AS3.(2) Three spliceosomes were higher enriched in the semimembranosus and longissimus muscles, while their expression was lower in the myocardium. The expression of MEF2C-AS1 in the myocardium tended to rise with age, while MEF2C-AS2 and MEF2C-AS3 decreasd.(3) Total eight mutations were identified in exons of MEF2C gene. One was found in exon 4(C61T), one in exon 8(C715T), and six in exon 14 (C4114T, A4486G, A4728C, C4869T, C5044T, and A6658G). The A4486G, A4728C, C4869T, and C5044T in Nanjiang yellow goat were in Hardy-Weinberg equilibrium. A4486G locus was in low-level polymorphism (PIC<0.25), but A4728C, C4869T and C5044T were in moderate polymorphisms (0.25< PIC< 0.5).(4) The withers heights of 2 months old rams with CC genotype were significantly higher than those of AA and AC genotype at A4728C; at 6 months old, ram with CC genotype at C4869T site were significantly higher than those of CT genotype. The birth weight of female kids with CTAATTCC genotype were significantly heavier than those with CCACCTCC genotype.(5) Body length, body height and chest have a very significant effect on body weight, with the growth of Nanjiang yellow goat. The bust contribution to the weight is the largest, and mainly affects by acting directly. Among this use the growth curve model (y= e(a+bx) with data of bust to estimate the body weight is the most accurate.