Abstract Protein phosphatase 2A (PP2A) is a ubiquitously expressed serine-threonine phosphatase mediating protein dephosphorylation to regulate the activities of many key pathways. PP2A is a heterotrimeric including catalytic subunit, structural subunit and regulatory subunit. To clone the coding sequence and analyze the character of expression and function of protein phosphatase 2A catalytic subunit α gene (PPP2CA), the specific primers of PPP2CA gene of Banna mini-pig (Sus scrofa) inbred line (BMI) was designed and the coding sequence was amplified using the PPP2CA mRNA sequences of pig and other species from GenBank as reference sequences. qRT-PCR was used to detect expression profiles of tissues mRNA. At the same time, the amino acid sequences were analysed by functional bioinformatics. A complete coding sequence of 930 bp of BMI PPP2CA was obtained, which encoded 309 amino acids. Comparing with other tissues, the PPP2CA gene expression in the urethral ball glands and seminal vesicle appeared extremely significance (P＜0.01). The expression in the testis was higher than other tissues. It was expressed moderately in the liver, colon, spleen, lung, duodenum, prostate, kidney, epididymis and brain, weakly in the stomach, heart and muscle. Functional prediction of PPP2CA protein indicated that the PPP2CA contained one conserved domain MPP_PP2A_PP4_PP6 and four kinds functional active sites, without transmembrane helix and signal peptide. The N-terminal and C-terminal were hydrophilic and located in cytoplasmic with 94.1%. It was predicted that the α helices content of the second structure were the highest which were the major structure of the N terminal, while the random coils were the major structure of the C terminal. The high similarity of PPP2CA amino acids alignment between BMI and other species indicated that this gene was highly conservative in evolution. This research can lay a further foundation for clarifying mechanism of the PPP2CA gene on sperm capacitation.
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