In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.
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Question:  In K562 cells , using the bicistronic vector , selection with colchicine led to at least 20 - fold higher expression of the MDR1 gene product than did selection with G418 , suggesting that the stringent MDR1 selection system is very efficient for obtaining overexpression of foreign genes .

Answer: MDR1 gene product


Question:  A novel serine kinase activated by rac1 / CDC42Hs - dependent autophosphorylation is related to PAK65 and STE20 .

Answer: serine kinase


Question:  Serum prolactin and oestradiol levels at different stages of puberty .

Answer:
Serum prolactin