Establishment of a suitable control reporter plasmid of a dual luciferase reporter gene system for hormone research in silkworm cell lines / 生物工程学报

The dual luciferase reporter gene system provides sensitive readout, while it relies on a constitutively-expressed control gene for readout normalization. However, most standard control reporter genes are not constitutively expressed under all conditions. Here, we report an effective method to construct a control reporter plasmid for the dual luciferase reporter gene system that would be suitable for hormone research in silkworm cell lines. First, we modified BmVgP78M, a stably-expressed constitutive promoter in silkworm cells by mutating its hormone-related element. Then, we constructed the pRL-VgP78M control reporter plasmid by replacing the SV40 promoter and chimeric intron sequences in pRL-SV40 with the BmVgP78M sequence. Finally, we confirmed that the pRL-VgP78M control reporter plasmid could be stably expressed in silkworm cell lines via cell transfection experiments, and it was unresponsive to the induction of ecdysone, juvenile hormone, or their transcription factors. We thus obtained a control reporter plasmid pRL-VgP78M that could be expressed stably and moderately in silkworm cells. It can be readily used as the control reporter plasmid of the dual luciferase reporter gene system for hormone research in silkworm cell lines. It will also provide a reference for construction of control reporter plasmids of dual luciferase reporter gene systems that are adaptable to cell lines isolated from other species.

Establishment of a reporter gene system for activity detection of hepatocyte nuclear factor 4α / 第二军医大学学报

Objective To establish a luciferase reporter gene system for detecting the activity of hepatocyte nuclear factor 4α (HNF4α), so as to screen the small molecule compounds regulating the activity of HNF4α. Methods HNF4α was purified by affinity chromatography. The direct interaction of DNA fragment or small molecule compounds to the HNF4α was determined by protein thermal shift assay. The constructing recombinant plasmid pGL3-NINJ1-3p or pGL3-NINJ1-9p, which contained three copies or nine copies of the HNF4α response element in the Ninjurin 1 (NINJ1) promoter, was transfected into hepatoma carcinoma cells. The transcriptional activity of HNF4α was detected by dual-luciferase reporter gene assay. The expressions of HNF4α and its down-stream genes were analyzed in hepatoma carcinoma cells treated with small molecular compound luteolin or alverine by real-time quantitative PCR. The changes of HNF4α transcriptional activity of cells treated with luteolin or alverine were estimated by luciferase reporter gene assay. Results Protein thermal shift confirmed that the HNF4α response element in NINJ1 promoter bound to HNF4α protein. In the hepatoma carcinoma cells with overexpression of HNF4α, both pGL3-NINJ1-3p and pGL3-NINJ1-9p could detect the alteration of the transcriptional activity of HNF4α, and pGL3-NINJ1-9p was more sensitive than pGL3-NINJ1-3p (P<0.01). Luteolin and alverine, both directly interacting with HNF4α, down-regulated and up-regulated the expression of HNF4α target genes, respectively. Moreover, pGL3-NINJ1-9p could validate the effect of luteolin or alverine on the transcriptional activity of HNF4α. Conclusion We successfully establish a detection system for HNF4α activity in hepatoma carcinoma cells by the reporter gene vector pGL3-NINJ1-9p. This system is a tool for screening small molecule compounds that regulate HNF4α activity.

Construction and verification of NF-κB luciferase reporter gene system / 生物工程学报

To quantify the transcriptional activity of NF-κB and to screen drugs related to the regulation of NF-κB activation, we constructed a recombinant plasmid through deleting the original CMV promoter of retrovirus vector pQCXIP and inserting the NF-κB enhancer and NanoLuc luciferase sequence into the vector. Then, using the recombinant plasmid we constructed a cell line in which the expression of NanoLuc luciferase (NLuc) was regulated by NF-κB. The inserted sequences were verified by restriction endonuclease digestion and sequencing. Tumor necrosis factor-α (TNF-α), an NF-κB activator, acted on the constructed NLuc cell line and leaded to the specific luciferase reaction. The luciferase reaction showed a fine time and dose dependence to the TNF-α stimulation, indicating the successful construction of the NF-κB regulated NLuc-expressing cell line. Besides, the NF-κB inhibitor, triptolide, reduced the expression of NLuc in a dose-dependent way. The constructed reporter system in this study could be applied in the quantification of the NF-κB transcriptional activity and in the NF-κB regulation-related drug screening.

The identification of human microRNA335′s predicated target gene CCL1 1,CCL26 and SOX4 / 重庆医学

Objective To identify the targeted-regulating relationship between human MicroRNA335 (hsa-miR-335 )and CCL1 1,CCL26 and SOX4.Methods The potential fragments of hsa-miR-335 target genes CCL1 1,CCL26 and SOX4 were predicted by the bioinformatics analyzing tools online.The 3′untranslated regions(3′UTR)of the CCL1 1,CCL26 and SOX4 were connected to the eukaryotic expression vectors pMIR REPORT.The constructs of pMIR-REPORT-CCL1 13′UTR,pMIR-REPORT-CCL26 3′UTR,pMIR-REPORT-SOX4 3′UTR and positive control were co-transfected with Pre-miRTM miRNA335 Precursor or negative control into 293 T7/1 7 cell line by lipofectamine 2000,respectively.Both Firefly and Renilla luciferase activity were detected by dual luciferase reporter assay system.Results Compared with the negative control group,luciferase assay revealed that has-miR-335 could significantly diminish luciferase activity from SOX4 reporter vector (P 0.05).Conclusion The results suggested that hsa-miR-335 targeted regu-lated SOX4,but not targeted CCL1 1 and CCL26.