【Objective】 To construct the Rb luciferase reporter gene assay system and detect the activation ability of Rb gene for screening the targeted drugs. 【Methods】 The synthetic Rb gene sequence was annealed to form a double-stranded DNA structure and then inserted into the polyclonal site of pGL6-TA. The junction product was transformed into E.coli DH5α competent cells for expanded culture, and the constructed pGL6-Rb-Luc plasmid and pGL6-TA plasmid were transfected into HEK293 cells. The monoclonal cell line HEK293-Rb-Luc with stable expression was screened by G418, and the activation and inhibition of Rb in HEK293-Rb-Luc were tested by serum and CDK4/6 inhibitor Palbociclib. 【Results】 The sequence of Rb reaction elements in pGL6-Rb-Luc was completely correct. The recovery of serum culture significantly increased the luciferase activity in HEK293-Rb-Luc (P<0.001). Compared with 0 nmol/L, 25, 50, 75 and 100 nmol/L, CDK4/6 inhibitor Palbociclib made the inhibition rate of Rb activity rise to 6.90%, 40.23%, 50.57% and 52.07%, respectively (P<0.05). 【Conclusion】 The Rb luciferase reporter gene detection system HEK293-Rb-Luc was successfully constructed, which can effectively detect the activation level of Rb.

【Objective】 To clone the full-length of human kidney and brain protein (KIBRA) coding sequence in eukaryotic expression vector and provide a model for studying the biological function of KIBRA in breast cancer cells. 【Methods】 Total RNA of human breast cancer cell line MCF7 was extracted. After reverse transcription, the full length of KIBRA (NM_001161661.2) coding region was amplified by PCR, and cloned into eukaryotic expression vector pCMV-Blank. After identification, it was defined officially as pCMV-KIBRA. Then it was transfected into MCF7 cells, and the expression of KIBRA was detected by real-time PCR and Western blotting after 48 hours. The primary, secondary and tertiary structures and post-transcriptional modification sites of KIBRA were analyzed with bioinformatics software. 【Results】 Bacterial PCR, double enzyme digestion and DNA sequencing results showed that the correct sequence of KIBRA was inserted into the vector pCMV-KIBRA. The mRNA and protein expressions of KIBRA were significantly increased in MCF7 cells transfected with pCMV-KIBRA. Bioinformatics analysis showed that KIBRA was composed of 1119 amino acids. There were 52 phosphorylation sites, 1 acetylation site and 5 ubiquitination sites, and the protein structure was mainly α-helix and random coil. 【Conclusion】 The eukaryotic expression vector of full-length of human KIBRA coding sequence was successfully constructed and overexpressed in breast cancer cell line MCF7, which can lay a foundation for studying the biological function of KIBRA in breast cancer.