Identification and function of a shrimp white spot syndrome virus (WSSV) gene that encodes a dUTPase

The ORF wsv112 of shrimp white spot syndrome virus (WSSV) was predicted to encode a protein with five conserved motifs at its N-terminus characteristics of dUTPases. The transcription of the gene named as wdut was analyzed by RT-PCR and RACE. The C-terminal end of the putative WSSV dUTPase bore very low similarity to the reported dUTPases and any other known proteins. Therefore, the 5′-terminal region (528-bp) of wdut gene was expressed in E. coli. The recombinant WSSV dUTPase (WDUT) with a molecular mass of 23 kDa could catalyze the hydrolysis of dUTP into dUMP and was highly specific for dUTP with an apparent Km of 1.2 μM. Furthermore, gel filtration results revealed that this enzyme was a trimer.