Long non-coding MEG3 is a marker for skeletal muscle development and meat production traits in pigs

Long non-coding RNAmaternally expressed gene 3 (lncRNAMEG3) plays an important role in mammalian muscle development. Our previous transcriptome study showed that lncRNAMEG3 is differentially expressed during postnatal skeletal muscle development in pigs. The objective of the present study was to analyse the role of lncRNAMEG3 in prenatal and postnatal skeletal muscle development and investigate the association of MEG3 with meat production traits in pigs. We investigated the sequence conservation and temporal-spatial expression of lncRNAMEG3 and identified its core promoter and single nucleotide polymorphisms (SNPs). Our results show that MEG3 is conserved among pig, human and mouse and is expressed in a tissue-specific manner with high expression levels in kidney and leg and dorsal muscles. In addition, MEG3 is more abundant in prenatal muscle compared to postnatal muscle, and its expression peaks at gestational day 60. Notably, we observed almost no expression 40 days after birth. The core promoter of MEG3 is located upstream of the transcription initiation site between -447 and -40 bp. In our SNP linkage disequilibrium and association analyses, four of the 10 potential polymorphism sites were found to be associated with corrected back fat thickness and age to reach 100 kg (rs325797437, rs344501106, rs81286029 and rs318656749). In addition, three haplotypes were found to be associated with differences in corrected age to reach 100 kg (AAAT, AAAT/GGGC, GAAT/GGGC). Our results indicate that MEG3 regulates skeletal muscle development and is a candidate gene for improving meat production traits in pigs.