Three slow skeletal muscle troponin genes in small-tailed Han sheep (Ovis aries): molecular cloning, characterization and expression analysis.

To explore the basic characteristics and expressing profile of the three slow skeletal muscle troponin genes TNNC1 (Troponin C type 1), TNNI1 (troponin I type 1) and TNNT1 (troponin T type 1). Three purebred Dorper sheep and another three purebred small-tailed Han sheep were selected. The sequence of the genes from the small-tailed Han sheep was cloned using rapid amplification of cDNA ends and reverse transcription-polymerase chain reaction; The characteristics of the predicted amino acids sequences were analyzed using bioinformatics analysis software; Gene expression analyses were performed using quantitative reverse transcription PCR. The full-length cDNA sequences of the genes were 707, 898, and 1001 bp, respectively, and were submitted to GenBank under accession numbers KR153938, KT218688 and KT218690. The three predicted proteins were predicted to be hydrophilic, non-secretory proteins and contain several phosphorylation sites. Multiple alignments and phylogenetic tree analyses showed that the predicted proteins were relatively conserved in mammals. The expression results of the three genes in eight tissues of Dorper and small-tailed Han sheep revealed that the three genes had a similar mRNA expression pattern, whereas distinct differences were observed among the eight tissues of the two sheep species. We cloned the full-length cDNA of the three genes, analyzed the amino acid sequences, and determined the expression levels of the genes. These results might play important roles in facilitating the future research of the three genes.