2534
Using bacterial artificial chromosome technology , we constructed a viral recombinant containing a mutation in the 5 ' splice donor site that defines the 5 ' end of the RNA and found that this mutation eliminates expression of the 5 - kb RNA during viral infection .
 chromosome
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Anatomy 
Text: {0} 
Answer:
 chromosome