1923
To identify additional non - Sir factors that affect rDNA silencing , we performed a genetic screen designed to isolate mutations which alter the expression of reporter genes integrated within the rDNA .
 GENE: Sir factors
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: Sir factors