911
Among the few proteins of the eukaryotic nucleolus that have been characterized , four proteins , nucleolin , fibrillarin , SSB1 and NSR1 , possess a common structural motif , the GAR domain , which is rich in glycine and arginine residues .
 nucleolin, fibrillarin, SSB1, NSR1
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 nucleolin, fibrillarin, SSB1, NSR1