Molecular cloning and functional analysis of MRLC2 in Tianfu, Boer, and Chengdu Ma goats

To determine the molecular basis of heterosis in goats, fluorescence quantitative polymerase chain reaction (PCR) was performed to investigate myosin-regulatory light chain 2 (MRLC2) gene expression in the longissimus dorsi muscle tissues of the Tianfu goat and its parents, the Boer and Chengdu Ma goats. The goat MRLC2 gene was differentially expressed in the crossbreed, and the purebred mRNA were isolated and identified using fluorescence quantitative reverse transcription-PCR (RT-PCR). The complete coding sequence of MRLC2 was obtained using the cDNA method, and the full-length coding sequence consisted of 513 bp encoding 172 amino acids. The EF-hand superfamily domain of the MRLC2 protein is well conserved in caprine and other animals. The deduced amino acid sequence of MRLC2 shared significant identity with MRLC2 from other mammals. Phylogenetic tree analysis revealed that the MRLC2 protein was closely related to MRLC2 in other mammals. Several predicted miRNA target sites were found in the coding sequence of caprine MRLC2 mRNA. Analysis by RT-PCR showed that MRLC2 mRNA was present in the heart, stomach, liver, spleen, lung, small intestine, kidney, leg muscle, abdominal muscle, and longissimus dorsi muscles. In particular, the high expression of MRLC2 mRNA was detected in the longissimus dorsi, leg muscle, abdominal muscle, stomach, and heart, but low levels of expression were also observed in the liver, spleen, lung, small intestine, and kidney. The expression of the MRLC2 gene was upregulated in the longissimus dorsi muscle of Boer and Tianfu goats, and it was moderately upregulated in Chengdu Ma goats.