3878
To determine the role of the transmembrane region of HN on fusion - promoting activity , mutant HN proteins were expressed and their biological activities examined .
 GENE: HN; GENE: mutant HN proteins
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: HN; GENE: mutant HN proteins