As a key regulatory element of gene differential expression, enhancer plays a crucial role in craniomaxillofacial development through regulating the spatiotemporal expression of target genes to promote tissue-specific differentiation. With the development of CRISPR and chromosome conformation capture technique, the function of enhancer and its regulatory mechanism has been explored in depth. This paper gave a systematic review on the mechanism of enhancer regulating target gene expression and the role of enhancer in oral craniofacial development and malformation.
Animals ; Enhancer Elements, Genetic ; Mammals/genetics*

OBJECTIVE: To explore the effect of rare synonymous variants of the ATP7B gene on the splicing of its precursor mRNA. METHODS: A total of 248 rare synonymous variants with allelic frequency of <0.005 were retrieved from the ExAc database. Human Splicing Finder (HSF) was used to predict their effect on the splicing of precursor mRNA. And ESE Finder 3.0 was used to predict the effect of such variants on the binding ability of SR protein family. Rare synonymous variants affecting the binding of two or more SR proteins were selected and verified with an in vitro mini gene splicing report system. RESULTS: HSF analysis indicated that 136 of the 248 rare synonymous variants may destroy the exonic splicing enhancer (ESE) motif. Analysis using ESE Finder 3.0 indicated that 19 of them may affect the binding of two or more SR proteins at the same time. In vitro mini gene experiment confirmed that the c.1620C>T (p.L540L) and c.3888C>T (p.A1296A) variants could lead to abnormal splicing of the corresponding exons, resulting in complete skipping of exon 4 and 25% increase in the skipping of exon 18, respectively. CONCLUSION Synonymous variants may affect the splicing of precursor mRNA in various ways, particularly the destruction of ESE motif. This study confirmed that the c.1620C>T (p.L540L) and c.3888C>T (p.A1296A) variants can affect the mRNA splicing of the ATP7B gene, resulting in skipping of corresponding exons, which may provide a basis for genetic diagnosis and consultation of carriers.
Alternative Splicing ; Copper-Transporting ATPases/genetics* ; Enhancer Elements, Genetic ; Exons ; Gene Frequency ; Humans ; RNA, Messenger/genetics*

In order to investigate the feasibility of using EGFP as a reporter gene in WT1 transcriptional regulation study. WT1 promoter and enhancer were ligated into the vector pEGFP-1 by recombinant DNA technique and confirmed by restriction enzymes digestion. The resultant constructs were transfected into K562 cell line by DMRIE-C reagent and the function of these WT1 gene elements was detected by using a fluorescent microscope after transfection for 48 hours. The results indicated that the recombinant vectors, pEWP containing WT1 promoter, and pEWPE, pEWPA and pEWPD harboring both WT1 enhancer and promoter, had been successfully constructed. Fluorescence was observed in K562 cells transfected by pEWP, pEWPE, pEWPA and pEWPD, while no fluorescence could be detected in cells transfected by pEGFP-1. It is concluded that EGFP gene as a reporter gene can be applied to the WT1 transcriptional regulation study, which provides the basis for gene therapy.
Enhancer Elements, Genetic ; genetics ; Genes, Reporter ; genetics ; Green Fluorescent Proteins ; genetics ; Humans ; K562 Cells ; Transfection ; WT1 Proteins ; genetics

OBJECTIVETo screen enhancer-like sequences from vaccinia virus genome, to construct an expression vector harboring prokaryotic enhancer-like sequence and study the effect of interferon gene expression.

METHODSEnhancer-like element from vaccinia virus genome was obtained by using the chloramphenicol acetyl-transferase cat gene as reporter gene. An expression vector harboring prokaryotic enhancer-like sequence VV1 from vaccinia virus was constructed. Interferon was expressed and assayed.

RESULTSEighteen enhancing sequences were found. From them two enhancer-like sequences with distance and orientation independence property were screened and named VV1 and VV16 respectively. Quantification test showed that the direct and reverse orientation of VV1 could increase the activity of beta-galactosidase with 10.9 and 3.8 times and those of VV16 could increase by 9.0 times and 4.1 times respectively. The enhancing activity of the element was on transcription level. An expression vector harboring prokaryotic enhancer-like sequence VV1 was constructed. Using this vector the antiviral activity of interferon alpha-2b was increased by 2.6 times in comparison with the original expression plasmid.

CONCLUSIONTwo enhancer-like sequences were screened from vaccinia virus genome. Interferon gene was highly expressed by using an expression vector harboring enhancer-like sequences.

Enhancer Elements, Genetic ; Genetic Vectors ; genetics ; Interferon-alpha ; biosynthesis ; genetics ; pharmacology ; Plasmids ; Recombinant Proteins ; Vaccinia virus ; genetics

OBJECTIVETo learn the effect of hepatitis B virus (HBV) sequence nt250-453 on the HBV X promoter.

METHODSA plasmid pNRE-XP which contains the NRE and the HBV X promoter was constructed to co-transfect HepG2 cell line with plasmid RL-TK. The firefly luciferase activity and mRNA expression of the firefly luciferase gene were both detected. Then, nt250-453 of HBV was removed from LJ196, which contained HBV full genes. The mutated plasmid LJ196 and plasmid LJ96 which provided core protein and the viral DNA polymerase were used to co-transfect HepG2 cell line. Reverse transcription polymerase chain reaction (RT-PCR) was performed to detect the X gene mRNA level.

RESULTSThe activity of firefly luciferase and the expression of firefly luciferase gene mRNA were both down-regulated in the presence of the NRE, while the HBV X gene mRNA expression increased as it was removed from the HBV genes.

CONCLUSIONThis study demonstrates that nt250-453 of HBV acts as a novel negative regulatory element which could suppress the HBV X promoter activity.

Enhancer Elements, Genetic ; Gene Expression ; Gene Expression Regulation, Viral ; Hepatitis B virus ; genetics ; Promoter Regions, Genetic ; Trans-Activators ; genetics

By altering the electrostatic charge of histones or providing binding sites to protein recognition molecules, Chromatin marks have been proposed to regulate gene expression, a property that has motivated researchers to link these marks to cis-regulatory elements. With the help of next generation sequencing technologies, we can now correlate one specific chromatin mark with regulatory elements (e.g. enhancers or promoters) and also build tools, such as hidden Markov models, to gain insight into mark combinations. However, hidden Markov models have limitation for their character of generative models and assume that a current observation depends only on a current hidden state in the chain. Here, we employed two graphical probabilistic models, namely the linear conditional random field model and multivariate hidden Markov model, to mark gene regions with different states based on recurrent and spatially coherent character of these eight marks. Both models revealed chromatin states that may correspond to enhancers and promoters, transcribed regions, transcriptional elongation, and low-signal regions. We also found that the linear conditional random field model was more effective than the hidden Markov model in recognizing regulatory elements, such as promoter-, enhancer-, and transcriptional elongation-associated regions, which gives us a better choice.
Binding Sites ; Chromatin ; genetics ; Enhancer Elements, Genetic ; Epigenomics ; Histones ; genetics ; Humans ; Markov Chains ; Models, Genetic ; Models, Statistical ; Promoter Regions, Genetic ; Regulatory Elements, Transcriptional

Chromosome Mapping ; Enhancer Elements, Genetic ; Erythropoietin ; genetics ; Exercise ; Humans ; Military Personnel ; Physical Endurance ; Polymorphism, Single Nucleotide ; Young Adult

To establish a transgenic cell model based on anti-oxidative response element (ARE) and green fluorescence protein(GFP) reporter gene, the TK minimal promoter was amplified by PCR and cloned into pEGFP-N1 for constructing reporter vector pTK-GFP/Neo. Four synthetic oligonucleotide ARE motifs were annealed and purified and then were inserted into pTK-GFP/Neo one by one to construct the eukaryotic reporter vector p4ARE-TK-GFP/Neo. Two reconstruct eukaryotic reporter vectors were transfected into HepG2 cells mediated by lipofectamine. The positive clones were obtained by the screen of G418. The cell model was tested with PDTC and tBHQ, well known inducers of phase II enzymes, by determining GFP activity. The results showed that the expression level of GFP was significantly increased by PDTC and tBHQ, and a transgenic cell model based on ARE was established successfully.
Antioxidants ; metabolism ; Base Sequence ; Enhancer Elements, Genetic ; genetics ; Genetic Vectors ; genetics ; Green Fluorescent Proteins ; biosynthesis ; genetics ; Hep G2 Cells ; Humans ; Molecular Sequence Data ; Response Elements ; genetics ; Thymidine Kinase ; biosynthesis ; genetics ; Transfection ; Transgenes

The objective of study was to investigate tissue-specific transcriptional activity of WT1 (Wilms' tumor gene) promoter and enhancer in cell lines with diverse tissue origin for leukemic gene therapy depending on WT1 transcriptional regulation elements. WT1 promoter and enhancer were ligated into pEGFP-1 to construct a recombinant vectors with EGFP gene as a reporter. By using electroporation or lipofectamine, the resultant constructs were transfected into 13 cell lines including WT1-expressing hematopoietic cell lines (K562, NB4, THP-1 and SHI-1), WT1-nonexpressing hematopoietic cell lines (U937 and Jurkat), WT1-expressing nonhematopoietic cell lines (MCF-7, T47D and 293) and WT1-nonexpressing nonhematopoietic cell lines (ECV304, SMMC7721, HT-29 and SHG44). The mean fluorescence intensity (MFI) of EGFP representing the transcriptional activities of promoter and/or enhancer was analyzed by using flow cytometry in the transfected cells which stably expressed EGFP. The results indicated that the vectors, pEWP containing WT1 promoter and pEWPA containing both WT1 enhancer and promoter, were constructed by recombinant DNA technique. Among nonhematopoietic cell lines, pEWP induced the highest EGFP expression in ECV304 (16.54 +/- 2.45 times as high as pEGFP-1), mildly higher in MCF-7 and SHG44 (9.46 +/- 1.10 and 7.29 +/- 0.73 times of pEGFP-1 level), and lowest in HT-29 (0.99 +/- 0.02 times as much as pEGFP-1) respectively. Among hematopoietic cell lines, EGFP expression was highest in K562 cell line (2.93 +/- 0.27 times of pEGFP-1), which was statistically higher than those in Jurkat and SHI-1 cell lines (0.74 +/- 0.03 and 0.84 +/- 0.09 times of pEGFP-1 level) respectively. pEWPA, with WT1 enhancer inserted at Afl II site near SV40 polyA, increased basal transcription levels of the WT1 promoter in HT-29, SHI-1 and K562 cells by 4.81, 3.06 and 1.01-fold respectively. It is concluded that the transcriptional activities of WT1 promoter in the recombinant vector seem unrelated to the constitutional expression level of endogenous WT1 gene. The WT1 enhancer promotes the transcriptional activities of WT1 promoter in some of the cell lines regardless of the hematopoietic tissue origin.
Enhancer Elements, Genetic ; genetics ; Humans ; Jurkat Cells ; K562 Cells ; Promoter Regions, Genetic ; genetics ; Transcription, Genetic ; U937 Cells ; WT1 Proteins ; genetics ; metabolism

OBJECTIVETo test whether the diphtheria toxin A (DT-A) chain coding sequence linked to murine immunoglobulin Kappa light chain (IgKappa) promoter and enhancer have selective cytocidal effects on IgKappa producing cells.

METHODSThe diphtheria toxin A gene or beta galactosidase (beta-gal) gene were linked to a murine IgKappa promoter and enhancer to construct pcDNA3IgKappaDTA or pcDNA3IgKappaLacZ plasmids. These plasmids were transfected into IgKappa producing or non-producing cells by the liposome coated DNA method. Expression of beta-gal activity and effects on cell growth of transfected cells were assessed.

RESULTSThe beta-gal gene, under the control of cytomegalovirus (CMV) promoter, can express in all cell lines. Expression of beta-gal under the control of the IgKappa promoter was detected only in the IgKappa producing cell line, CA46. Expression of beta-gal was greatly suppressed when cotransfected with pcDNA3IgKappaDTA in CA46 cells. Cell growth of CA46 cells transfected with pcDNA3IgKappaDTA plasmid was significantly inhibited compared with CA46 cells transfected with pcDNA3IgKappaLacZ.

CONCLUSIONSelective killing of IgKappa producing cells can be attained by introducing the diphtheria toxin A gene under the control of IgKappa promoter and enhancer.

Diphtheria Toxin ; genetics ; Enhancer Elements, Genetic ; Genes, Immunoglobulin ; Genetic Therapy ; methods ; Humans ; Immunoglobulin kappa-Chains ; genetics ; Neoplasms ; therapy ; Peptide Fragments ; genetics ; Promoter Regions, Genetic ; Tumor Cells, Cultured