ABSTRACT
【Objective】 To construct the eukaryotic expression vector carrying the human wild-type p27 and lacking nuclear localization signal p27△NLS coding sequences， and the express them in HEK293T cells， which may contribute to investigating the different locations and roles of p27 in the cytoplasm and nucleus. 【Methods】 Total RNA was prepared from human breast cancer MCF7 cells， and cDNA was obtained by reverse transcription-polymerase chain reaction （RT-PCR）. After amplification of the p27 CDs and non-NLS fragments by PCR， full length p27WT （CDKN1B， NM_004064.5） and p27△NLS coding regions were obtained. PCR products were then subcloned into the eukaryotic expression vector pCMV-Blank. After identification with bacterial PCR， double restriction enzyme digestion and sequencing， they were defined officially as pCMV-p27WT and pCMV-p27△NLS， respectively. The recombinant plasmids were transfected into HEK293T cells by electroporation. After 48 h， the levels of p27 protein in the cytoplasm and nucleus were detected by Western blotting. 【Results】 The sequencing results showed that the sequences of p27WT and p27△NLS inserted into the plasmids were both correctly consistent with that of NM_004064.5. After transfection with pCMV-p27WT， total p27 protein expression was increased and distributed in both the cytoplasm and nucleus of HEK293T cells. After transfection with pCMV-p27△NLS， p27 protein was significantly increased and almost entirely localized in the cytoplasm of HEK293T cells. 【Conclusion】 The eukaryotic expression plasmids of human p27WT and p27△NLS coding sequences were successfully constructed and overexpressed in HEK293T cells. This research may lay a foundation for investigating the biological function of p27 in the cell cycle progression of tumor cells.
ABSTRACT
【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.
ABSTRACT
【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.