5148
Phosphorylation of the retinoblastoma protein by cyclin-dependent kinases 4 and 6 prevents its interaction with the transcription factor E2F , which subsequently promotes the expression of S phase regulated genes , such as thymidine kinase .
 protein: retinoblastoma protein; DNA: S phase regulated genes; protein: thymidine kinase; protein: E2F; protein: transcription factor
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
 Entities: retinoblastoma protein, S phase regulated genes, thymidine kinase, E2F, transcription factor 
Answer:
 protein: retinoblastoma protein; DNA: S phase regulated genes; protein: thymidine kinase; protein: E2F; protein: transcription factor