6598
Although a great deal is understood about how bHLH factors activate gene transcription via E - box DNA consensus sequences , studies of bHLH factor function in higher eukaryotes often have been hindered by the presence of multiple family members .
 GENE: bHLH factors; GENE: bHLH factor
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
 Entities: bHLH factors, bHLH factor 
Answer:
 GENE: bHLH factors; GENE: bHLH factor