Identification, mRNA expression and characterization of proliferating cell nuclear antigen gene from Chinese mitten crab Eriocheir japonica sinensis

The sliding clamp proliferating cell nuclear antigen (PCNA) plays important roles in nucleic acid metabolism. In this work, we isolated a PCNA gene (designated as EjsPCNA, accession: FJ483830) by rapid amplification of cDNA ends approach from the Chinese mitten crab Eriocheir japonica sinensis. The full-length cDNA of EjsPCNA consists of 1123 nucleotides with an open-reading frame of 780 bp encoding 259 amino acids (28.62 kDa) and containing an interdomain connecting loop, C-terminal tail, and center loop. Sequence alignment, phylogenetic analyses, and structure comparison revealed that EjsPCNA is a member of the PCNA family. Real-time RT-PCR results indicate that EjsPCNA is expressed throughout three developmental stages. EjsPCNA mRNA expression levels at the first crab stage are significantly higher than that of the other two stages. Present data showed that the expression levels of EjsPCNA in E. j. sinensis are likely related to proliferation activity of tissues, and suggested that EjsPCNA gene is probably involved in the crabs' early developmental regulation.