The genes hutWEp, hutXEp, and hutZEp are co-transcribed. Total RNA was isolated from Edwardsiella piscicida TX01 at a turbidity of 1.0 at 600 nm and treated with DNase I. cDNA was synthesized and used as the template in PCR. PCR products were amplified with specific primers for hutWEp and hutXEp, hutXEp and hutZEp. Genomic DNA was used as a positive control, and total RNA was used as a negative control. M indicates a DNA ladder.