This study was aimed to establish a high-throughput luciferase reporter system, through which to screen and identify miRNAs directly targeting p21, and to explore the biological function and significance of these miRNAs. Molecular cloning technique was used to construct and identify two lentivirus-expressing vectors-pWPXL-Luc and pWPXL-Luc-P21-3'UTR, virus particles were collected after the pWPXL-Luc or pWPXL-Luc-P21-3'UTR vectors were co-transfected with the psPAX2 packaging plasmid and the envelope plasmid pDM2G into HEK-293T cells. Furthermore, two stable cell lines expressing luciferase singly or co-expressed luciferase and P21-3'UTR were established by transducing HEK-293 cells with recombinant lentivirus; the former was used as control in the following experiments. Finally luciferase activity of the latter stable cells was measured by using the luciferase reporter assay system. The results showed that high-titre recombinant lentivirus was produced and two stable cell lines were constructed, also to some certain, the luciferase activity was in direct proportion to the number of cells. In conclusion, the high-throughput luciferase reporter system is established successfully; using this system, the 28 miRNA that directly target P21 Cip1/Waf1 are screened experimentally.
Genes, Reporter ; Genetic Vectors ; HEK293 Cells ; Humans ; Lentivirus ; genetics ; Luciferases ; genetics ; MicroRNAs ; genetics ; Plasmids ; Transduction, Genetic

This study aimed to explore the effect of miR-23b-3p on the differentiation of goat intramuscular preadipocytes, and to confirm whether miR-23b-3p plays its roles via targeting the PDE4B gene. Based on the pre-transcriptome sequencing data obtained previously, the miR-23b-3p, which was differentially expressed in goat intramuscular adipocytes before and after differentiation, was used as an entry point. real-time quantitative-polymerase chain reaction (qPCR) was used to detect the expression pattern of miR-23b-3p during the differentiation of goat intramuscular preadipocytes. The effects of miR-23b-3p on adipose differentiation and adipose differentiation marker genes were determined at the morphological and molecular levels. The downstream target genes of miR-23b-3p were determined using bioinformatics prediction as well as dual luciferase reporter assay to clarify the targeting relationship between miR-23b-3p and the predicted target genes. The results indicated that overexpression of miR-23b-3p reduced lipid droplet accumulation in goat intramuscular adipocytes, significantly down-regulated the expression levels of adipogenic marker genes AP2, C/EBPα, FASN, and LPL (P < 0.01). In addition, the expressions of C/EBPβ, DGAT2, GLUT4 and PPARγ were significantly downregulated (P < 0.05). After interfering with the expression of miR-23b-3p, lipid droplet accumulation was increased in goat intramuscular adipocytes. The expression levels of ACC, ATGL, AP2, DGAT2, GLUT4, FASN and SREBP1 were extremely significantly up-regulated (P < 0.01), and the expression levels of C/EBPβ, LPL and PPARγ were significantly up-regulated (P < 0.05). It was predicted that PDE4B might be a target gene of miR-23b-3p. The mRNA expression level of PDE4B was significantly decreased after overexpression of miR-23b-3p (P < 0.01), and the interference with miR-23b-3p significantly increased the mRNA level of PDE4B (P < 0.05). The dual luciferase reporter assay indicated that miR-23b-3p had a targeting relationship with PDE4B gene. MiR-23b-3p regulates the differentiation of goat intramuscular preadipocytes by targeting the PDE4B gene.
Animals ; MicroRNAs/metabolism* ; Goats/genetics* ; PPAR gamma/metabolism* ; Adipogenesis/genetics* ; Cell Differentiation/genetics* ; Luciferases ; RNA, Messenger

Genes, Reporter ; Genetic Vectors ; Luciferases ; genetics ; Transcription, Genetic ; bcl-2-Associated X Protein ; genetics

OBJECTIVETo investigate the expression characteristics of Gluc-Fluc dual luciferase plasmid after its transfection into MB49 bladder cells.

METHODSpAAV2neoCAG-Gluc-2A-Fluc and pAAV2neo-Gluc plasmids were separately transfected into MB49 cells via LipofectamineTM2000. The Gluc activity in the cell culture supernatant and the Fluc activity in the cells were detected by luminometer and Lumina Imaging system.

RESULTSThe luminometer result showed that the activity of Gluc in the supernatant increased gradually in a cell number- and time-dependent manner, while Fluc activity in the cells increased with the cell number but not with time. The Lumina Imaging system showed that Gluc-Fluc was successfully expressed in MB49 bladder cells and cell lines with stable Gluc-Fluc expression were obtained after G418 selection.

CONCLUSIONGluc in the dual luciferase plasmid retains its expression characteristics. Due to the advantages of Fluc in localization in living imaging and the easy quantitative detection of Gluc, the dual luciferase plasmid, after transfection in MB49 bladder cells, allows reliable and dynamic detection of tumor growth in animal models.

Animals ; Cell Line, Tumor ; Genetic Vectors ; Luciferases ; genetics ; metabolism ; Mice ; Plasmids ; genetics ; metabolism ; Transfection

To explore the activity of the pmel core promoter of Bashang long-tail chickens, we constructed dual-luciferase expression vectors and transiently transfected into DF1 cells with Lipofectamine 2000. We measured the luciferase activity with the dual-luciferase detection kit. The 1 268 bp fragment in 5-flanking region of the pmel gene in Bashang long-tail chickens was cloned. The region from -1 200 bp to +68 bp included 2 CpG islands and multiple transcription factor binding sites. We constructed 9 expression vectors with different promoter regions and a mutant vector of the core promoter region of the pmel gene of Bashang long-tail chickens. The core promoter region from -840 bp to +68 bp was identified in the pmel gene. The region from -590 to -525 bp negatively regulated the pmel gene during the transcription process. The -840--590 bp and -525--266 bp regions were positive regulatory regions. The polymorphic sites (-456, -435, -410, -374 and -341) had a significant effect on the promoter activity of the pmel gene.
Animals ; Chickens ; genetics ; Cloning, Molecular ; CpG Islands ; Luciferases ; Promoter Regions, Genetic ; gp100 Melanoma Antigen ; genetics

OBJECTIVETo establish an efficient method for screening effective small interference RNA (siRNA) using dual-luciferase reporter assay system.

METHODSBased on the siRNA expression vector pSilencer-4.1, 3 candidate green fluorescence protein (GFP) gene siRNA expression plasmids, namely pSi-GFPsiRNA1, pSi-GFPsiRNA2, and pSi-GFPsiRNA3, along with the negative control pSi-Negative, were constructed. Using the pGL3-promoter vector, the GFP-luciferase (GFP-LUC) expression plasmid pGL3-GFPf was constructed with the same Kozak consensus translation initiation site and start codon ATG for GFP-LUC coding sequence. The GFP fragment containing the target sequences of 3 GFP siRNAs was introduced into the 3' untranslate region of LUC in the modified pGL3-promoter vector to construct the plasmid pGL3-GFPp. The GFP siRNAs expression plasmids and Renilla luciferase reporter vector pRL-TK were co-transfected with pGL3-GFPf or pGL3-GFPp into the HEK293 cells, respectively. The luciferase activities were determined by dual-luciferase reporter assay, and the GFP mRNA expressions were detected by real-time quantitative PCR.

RESULTSIn the groups cotransfected with GFP siRNAs expression plasmids and pGL3-GFPf, the luciferase activities were reduced obviously, and the reduction was more significant in cells transfected with GFPsiRNA1 compared with the control cells (P<0.01).GFP mRNA levels were also markedly lowered in cells transfected with GFPsiRNA1 as shown by real-time PCR (P<0.01). In addition, the results of dual-luciferase reporter assay and real-time PCR showed that among the groups cotransfected with GFP siRNAs expression plasmids and pGL3-GFPp, the GFP expression was inhibited most obviously by GFPsiRNA1 (P<0.01).

CONCLUSIONThe dual-luciferase reporter assay system provides a useful method for screening effective siRNAs targeting specific genes.

Animals ; Cell Line ; Genes, Reporter ; Green Fluorescent Proteins ; genetics ; Luciferases ; genetics ; Plasmids ; genetics ; RNA Interference ; RNA, Small Interfering ; genetics ; Transfection

This study aims to develop an improved cell screening system for farnesoid X receptor (FXR) agonists based on a dual luciferase reporter gene system. FXR response element (FXRE) fragments from FXR target genes were cloned and inserted into upstream of firefly luciferase (Luc) gene in the plasmid pGL4-luc2P-Hygro. In combination with the internal reference plasmid containing renilla luciferase, a dual luciferase reporter gene system was developed and used for high throughput screening of FXR agonists. After studying the effects of over-expression of RXR, mouse or human FXR, various FXRE fragments, and different ratio of FXR plasmid amount to reporter gene plasmid, induction efficiency of the screening system was optimized by the known FXR agonist GW4064, and Z factor for the system reached 0.83 under optimized conditions. In summary, an improved cell screening system based on double luciferase reporter gene detection system was developed to facilitate the discovery of FXR agonists, where a new enhanced FXRE element was formed by a superposition of multiple FXRE fragments from FXR target genes, instead of a superposition of traditional IR-1 (inverted repeats-1) fragments.
Humans ; Mice ; Animals ; Transcription Factors/genetics* ; DNA-Binding Proteins/genetics* ; Receptors, Cytoplasmic and Nuclear/genetics* ; Genes, Reporter ; Luciferases/genetics*

OBJECTIVETo investigate the roles of Domain I and Domain II of hepatitis C virus (HCV) 5' untranslated region (UTR) in the translation initiation activity of HCV 5'UTR in different host cell lines.

METHODSThe eukaryotic expression plasmid pCMVNCRLuc (pCN1), in which full-length HCV 5'UTR regulates firefly luciferase expression, was modified by deleting Domain I and the downstream single-stranded sequence (43 bp in total) from the UTR (pCNl-d2), Domain I with the downstream single-stranded sequence and Domain II (118 bp in total) from the UTR (pCNl-d3), or the total UTR (pCNl-d5). The modified plasmids were transfected via liposome into different cell lines with pRL-TK plasmid co-transfected as the normalization control. At 36 h after the transfection, the total cellular RNA was harvested for semi-quantitative RT-PCR, and the relative expression activities of luciferase were assayed with a dual luciferase reporter gene assay system. The translation initiation activities of the truncated HCV 5'UTRs in different translation systems were analyzed.

RESULTSDeletion of Domain I and the downstream single-stranded sequence caused no significant changes of the translational activity of HCV 5'UTR in Hela or C6 cells, but decreased the translational activity by 46% in L-02 cells and increased the translational activity by 46% in 293T cells. Deletion of both Domain I and Domain II resulted in decreased translational activity of HCV 5'UTR by 51% in HeLa cells, but increased the translational activity by 40% in L-02 cells, 60% in C6 cells and 135% in 293T cells.

CONCLUSIONSDomain I and Domain II of HCV 5'UTR perform cell type-specific roles in HCV IRES-driven translation initiation.

5' Untranslated Regions ; Genes, Reporter ; HeLa Cells ; Hepacivirus ; genetics ; Humans ; Luciferases ; Plasmids ; Protein Biosynthesis ; genetics ; RNA, Viral ; genetics ; Transfection

This study was aimed to construct, package and purify the recombinant lentivirus vector carrying the firefly luciferase gene (FLUC) and red fluorescent protein gene (RFP) and to transfect the recombinant lentivirus into HeLa cells, so as to observe the expression levels of these two genes. The FLUC and RFP genes were amplified by RT-PCR and inserted in the lentiviral expression vector (pLenti-Bi-cistronic) to construct the lentiviral vector pLenti-FLUC-RFP. The viral particles were generated by cotransfection of 293T cells with pLenti-FLUC-RFP and three packaging vectors, and the virus titer was determined by calculating the percentage of RFP positive cells. After transfection of pLenti-FLUC-RFP into HeLa cells, the expression of RFP was observed by fluorescent microscopy, and the activity of FLUC was determined by luciferase reporter gene assay kit. The results showed that the inserting orientation of the RFP and FLUC genes in the lentiviral vector pLenti-FLUC-RFP were verified by restriction analysis. Targeted RFP and FLUC sequences were confirmed by DNA sequencing. The final titer obtained was 1×10(7)TU/ml. The expressions of RFP and FLUC were observed in the transfected HeLa cells. It is concluded that the pLenti-III-FLUC-RFP recombinant lentivirus vector carrying RFP gene and FLUC gene with high viral titer is constructed and packaged successfully, and provides experimental basis for studying dynamic distribution of mesenchymal stem cells in vivo.
Gene Expression ; Genes, Reporter ; Genetic Vectors ; HeLa Cells ; Humans ; Lentivirus ; genetics ; Luciferases, Firefly ; genetics ; Luminescent Proteins ; genetics ; Transfection

Pyrosequencing is a tool based on bioluminescence reaction for real-time analyzing DNA sequences. The sensitivity of pyrosequencing mainly depends on luciferase in reaction mixture. However, the instability of pyrosequencing reagents caused by fragile wild Photinus pyralis luciferase (PpL) in conventional pyrosequencing usually leads to unsatisfied results, which limits the application of pyrosequencing. In order to improve the stability of pyrosequencing reagents, the coding sequences of mutant thermostable Luciola lateralis luciferase (rt-LlL) was synthesized, and inserted into the plasmid of pET28a(+) to express the thermostable rt-LlL with a 6 x His-tag in the N terminal. The purified rt-LlL with the molecular mass of 60 kDa was obtained by Ni-affinity chromatography. The specific activity of rt-LlL was determined as 4.29 x 10(10) RLU/mg. Moreover, the thermostability of rt-LlL was investigated, and the results showed that rt-LlL had activity at 50 degrees C, and remained 90% of activity after incubated at 40 degrees C for 25 min. Finally, rt-LlL was used to substitute commercial Photinus pyralis luciferase in conventional pyrosequencing reagent to get thermostable pyrosequencing reagent. Comparing with conventional pyrosequencing reagent, the thermostable pyrosequencing reagent is more stable, and it's activity would not lose when incubated at 37 degrees C for 1 h. This study laid foundation of establishing reliable and stable pyrosequencing system which would be applied in Point-of-Care Testing.
Animals ; Enzyme Stability ; Escherichia coli ; genetics ; metabolism ; Fireflies ; enzymology ; Luciferases ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Sequence Analysis, DNA ; methods