The elimination of schistosomiasis, a parasitic disease caused by Schistosoma 
and a major source of morbidity and mortality in developing countries, faces 
serious challenges. Although the pumilio protein regulates the reproductive 
organ development in many species, its role in Schistosoma japonicum is unknown. 
Thus, this study investigated the function of pumilio in S. japonicum 
reproduction. The complete coding sequences of S. japonicum Pumilio1 (SjPum1) 
and SjPum2 genes were cloned and characterized. The full-length open-reading 
frame SjPum1 (2613 nucleotides) and SjPum2 (4479 nucleotides) genes were 
obtained. Bioinformatics analysis showed that those genes belonged to the PUF 
(pumilio and FBF) family. Quantitative polymerase chain reaction analyses 
revealed that SjPum1 and SjPum2 were differentially expressed throughout the S. 
japonicum life cycle and were highly expressed in reproductive organs. In situ 
hybridization results showed that mRNA expression of SjPum2 was higher than that 
of SjPum1 in the ovary and testis. Knocking down SjPum2 using RNA interference 
techniques to explore potential reproductive functions showed that compared with 
the control (untransfected or scrambled mRNA-transfected) worms, the morphology 
of both male and female reproductive organs was altered, the number of eggs 
produced by paired females was significantly decreased, and the transcription 
levels of caspase 3 and caspase 7 genes related to apoptosis were significantly 
increased. The transcription level of Nanos1 gene which related to reproduction 
was also significantly increased. Therefore, SjPum2 may play a role in the 
reproductive development of S. japonicum.