1559
To identify the DNA sequences that cis - regulate the expression of the rat liver pyruvate kinase ( L - PK ) genes , a series of constructs in which the chloramphenicol acetyltransferase reporter genes is driven by various deleted fragments of the 3200 base pairs ( bp ) upstream of the L - PK gene cap site have been assayed for transient expression after introduction into hepatoma HepG2 cells , rat hepatocytes in primary culture , fibroblast LTK - cells , myogenic C2C12 cells , and CHO cells .
 rat liver pyruvate kinase, L - PK, chloramphenicol acetyltransferase reporter genes, L - PK gene cap site
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 rat liver pyruvate kinase, L - PK, chloramphenicol acetyltransferase reporter genes, L - PK gene cap site