4483
These findings are consistent with a model for Rex -mediated trans-activation in which Rex -viral mRNA complexes are targeted for nuclear export by the direct action of the activation domain .
 protein: Rex; protein: Rex; protein: activation domain; protein: Rex -viral mRNA complexes
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
 Entities: Rex, Rex, activation domain, Rex -viral mRNA complexes 
Answer:
 protein: Rex; protein: Rex; protein: activation domain; protein: Rex -viral mRNA complexes