3765
Both purH and purD genes constitute a single operon and are coregulated in expression by purines as other purine genes are .
 GENE: purH; GENE: purD genes; GENE: purine genes
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
 GENE: purH; GENE: purD genes; GENE: purine genes