Molecular characterization and tissue expression profile of the Dnmts gene family in pig

DNA methyltransferases (Dnmts) comprise a family of proteins which involved in the establishment and maintenance of DNA methylation patterns. In pig, the molecular characterization and tissue expression profile of Dnmt gene family are not clear. To solve this problem, reverse transcriptase PCR and rapid amplification of cDNA ends were used to clone the sequences of the porcine Dnmt2 and Dnmt3b genes. Furthermore, the mRNA expression profiles of Dnmt1, Dnmt2, Dnmt3a and Dnmt3b genes from 54 adult tissues and 2 entire fetuses of Rongchang pig were analyzed by quantitative real-time PCR (qRT-PCR). As a result, the lengths of porcine Dnmt2 and Dnmt3b gene cDNAs were 1 227 and 2 559 bp with cytosine-C5 specific DNA methylase domain, respectively. The four Dnmt genes were highly expressed in longissimus dorsi muscle (P<0.01). Dnmt1 is highly expressed in heart (P<0.01) and Dnmt 2 shows its preference in liver and seminal vesicle tissue (P<0.01). Dnmt3a and Dnmt3b are highly expressed in the two fetus stages (P<0.01). All these results suggested that each gene has its specific expression profile, and deeper study is required to dig more details between the methylation level and Dnmt family mRNA expressions in different tissues.