439
Evidence from the structure of a number of cDNA clones , as well as S1 nuclease and primer extension studies supports the hypothesis that the PTHrP gene contains at least two mRNA transcription start points that define two putative regulatory domains .
 GENE: S1 nuclease; GENE: PTHrP gene
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: S1 nuclease; GENE: PTHrP gene