724
Northern blot analyses demonstrate that 3 . 9 - and 5 - kilobase mRNAs corresponding to the cDNA were present in all tissues examined , suggesting that the protein it encodes performs a housekeeping function .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 None