982
Transcript analysis reveals that lethal B block substitutions reduce U6 RNA synthesis at least 10 - fold in vivo and 20 - fold in vitro .
 GENE: B block; GENE: U6 RNA
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: B block; GENE: U6 RNA