7264
The requirement of Tyr - 19 dephosphorylation for spindle assembly is also observed under conditions in which spindle formation is independent of mitosis , suggesting that the involvement of Cdc28 / Clb kinase in SPB separation is direct .
 Cdc28, Clb
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 Cdc28, Clb