Molecular characterization of a phosphoserine aminotransferase gene in Antheraea pernyi and assessment of its value for phylogenetic inference

A gene encoding phosphoserine aminotransferase from Antheraea pernyi (ApPSAT) was isolated and characterized, and its value for phylogenetic inference was assessed. The resulting 1309 bp cDNA sequence contains an open reading frame of 1095 bp encoding a polypeptide of 364 amino acids, with 58% sequence identity to that from Homo sapiens. RT-PCR analysis showed that the ApPSAT gene was transcribed at four developmental stages, and in all examined tissues with the most abundance in malpighian tubules. Sequence alignment suggested that ApPSAT protein sequence exhibited 41–87% homology with the known PSATs from bacteria, fungi, plants, invertebrates and vertebrates. Phylogenetic analysis revealed that 37 representative PSAT protein sequences were well divided into five groups corresponding to the known fungi, bacteria, plants, invertebrates and vertebrates. The phylogenetic relationships obtained were consistent with the traditional classification and other molecular data, suggesting the potential value of the PSAT protein in phylogenetic inference.