Head title : Identification of novel MEF 2 A transcripts Novel Alternatively Spliced Isoforms of MEF 2 A and Their mRNA Expression Patterns in Pig

The present study aimed to identify alternatively spliced isoforms of pig MEF2A gene and determine their mRNA expression patterns. Four alternatively spliced isoforms of pig MEF2A gene (i.e., MEF2A1, MEF2A2, MEF2A3, and MEF2A4) were cloned according to the results of transcriptome sequencing. The fifth to eight exons of MEF2A1 were normally spliced. In MEF2A2, the fifth exon was missing; the sixth exon had an extra 138 bp at its 5' end, and the seventh exon had extra 102 bp at its 3' end. In MEF2A3, the fifth exon was missing, and the sixth exon had an additional 138 bp at its 5' end. In MEF2A4, the seventh exon had an extra 102 bp at its 3' end. Quantitative real-time PCR analysis indicated that the expression profiles of the four alternatively spliced transcripts in the longissimus dorsi differed between Mashen and Large White pigs. MEF2A1 and MEF2A2 expression was the highest at 90 days of age and the lowest at 180 days of age. MEF2A3 and MEF2A4 expression increased with age (in days). The four alternatively spliced isoforms of MEF2A were also expressed in the small intestine, cerebellum, pancreas, heart, and lung. The discovery of new alternatively spliced transcripts of MEF2A gene may be utilized in better understanding its biological functions.