6743
Sequence analysis of this 100 - bp Col2a1 enhancer revealed several sequence motifs similar to motifs present within the regulatory region of the link protein gene , another cartilage gene .
 Col2a1 enhancer, link protein gene
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 Col2a1 enhancer, link protein gene