Proliferating cell nuclear antigen (PCNA) is a member of the sliding clamp protein family that plays important roles in DNA replication, and is strongly expressed in proliferating tissues. Several studies have discovered other biological roles of PCNA, for example, in DNA repair, cell cycle regulation, and chromosome recombination. When culturing shrimp, the first problem is how to induce maturation of the ovary; therefore, it is important to understand ovarian development. We focused on PCNA because it plays an important role in cell proliferation. The PCNA gene ( using the rapid amplification of cDNA ends technique. The sequence encoded a protein of 260 amino acids that showed high homology to PCNA proteins from other species. The full-length cDNA was 978 bp long and contained a 5'-untranslated region (UTR) of 135 bp, a 3'-UTR of 60 bp, and an open reading frame of 783 bp. The protein was predicted to have a molecular weight of 28.83 kDa and an isoelectric point of 4.59. Analyses of transcript levels by quantitative real-time PCR indicated that it was transcribed in all tissues, with high transcript levels in the ovary and brain. During ovarian maturation, there were higher transcript levels of <0.05). Previous research has shown that 5-hydroxytryptamine (5-HT) can stimulate ovary growth and development. Injection of 5-HT resulted in increased transcript levels of in the ovaries, with the peak transcript levels at 48 h post-injection. The PmPCNA protein was successfully expressed in a prokaryote, providing a platform for further research. These results provide important information on the role of in the development of the shrimp ovary.