An efficient genetic transformation system and suitable promoters are essential prerequisites for gene expression studies and genetic engineering in streptomycetes. In this study, firstly, a genetic transformation system based on intergeneric conjugation was developed in Streptomyces rimosus M527, a bacterial strain which exhibits strong antagonistic activity against a broad range of plant-pathogenic fungi. Some experimental parameters involved in this procedure were optimized, including the conjugative media, ratio of donor to recipient, heat shock temperature, and incubation time of mixed culture. Under the optimal conditions, a maximal conjugation frequency of 3.05×10^-5 per recipient was obtained. Subsequently, based on the above developed and optimized transformation system, the synthetic promoters SPL-21 and SPL-57, a native promoter potrB, and a constitutive promoter permE^* commonly used for gene expression in streptomycetes were selected and their activity was analyzed using gusA as a reporter gene in S. rimosus M527. Among the four tested promoters, SPL-21 exhibited the strongest expression activity and gave rise to a 2.2-fold increase in β-glucuronidase (GUS) activity compared with the control promoter permE^*. Promoter SPL-57 showed activity comparable to that of permE^*. Promoter potrB, which showed the lowest activity, showed a 50% decrease in GUS activity compared with the control permE^*. The transformation system developed in this study and the tested promotors provide a basis for the further modification of S. rimosus M527.
Conjugation, Genetic ; Glucuronidase/genetics* ; Promoter Regions, Genetic ; Streptomyces rimosus/genetics*

BACKGROUNDNumerous studies have evaluated the association between interleukin-18 (IL-18) promoter gene -607C/ A (rs1946518) polymorphism and tuberculosis (TB) risk. However, the results remain apparently conflicting. The aim of this study was to investigate whether IL-18-607C/A polymorphism is associated with susceptibility to TB.

METHODSPublications addressing the association between the IL-18-607C/A polymorphism and TB risk were selected from the Pubmed, Cochrane Library, Embase, CNKI and Wanfang databases. Data were extracted from the studies by two independent reviewers. Statistical analysis was performed using RevMan 5.0.25 and STATA 11.0 software.

RESULTSEight case-control studies with a total of 1166 TB patients and 1734 controls were retrieved. Meta-analysis results showed significant association between IL-18-607C/A polymorphism and TB risk in all comparisons of the A allele versus C allele (OR=1.17, 95% CI 1.05-1.30, P=0.004), AA versus CC (OR=1.43, 95% CI 1.14-1.81, P=0.002), CA+AA versus CC (OR=1.20, 95% CI 1.01-1.42, P=0.04) and AA versus CA+CC (OR=1.30, 95% CI 1.07-1.58, P=0.007). In subgroup analysis by nationality, a significant association between IL-18-607C/A polymorphism and TB risk in the comparisons of A versus C, CA+AA versus CC and AA versus CA+CC (OR=1.22, 95% CI 1.07-1.38, P=0.002; OR=1.31, 95% CI 1.06-1.61, P=0.01; OR=1.32, 95% CI 1.07-1.63, P=0.01, respectively) were found in Chinese population but not in Indian and Iranian populations.

CONCLUSIONThis study suggests that the -607C/A polymorphism of IL-18 gene would be a risk factor for TB, especially in Chinese population. To further evaluate gene-to-gene and gene-to-environment interactions on -607C/A polymorphism and tuberculosis risk, more studies with thousands of patients are required.

Genetic Predisposition to Disease ; genetics ; Humans ; Interleukin-18 ; genetics ; Promoter Regions, Genetic ; genetics ; Tuberculosis ; epidemiology ; genetics

BACKGROUNDOsteoarthritis (OA) is the most common form of human polyarthritis. Many genetic factors have been implicated in OA. It was reported that a polymorphism in the gene of interleukin-6 (IL-6) was associated with OA of knee. The aim of this study was to determine whether functional IL-6 promoter -174G/C (rs1800795) polymorphisms confer susceptibility to knee OA.

METHODSA meta-analysis was conducted on the association between the IL-6 polymorphism and knee OA. Electronic search at PubMed, EMBASE, Weipu database, and Wanfang database was conducted to select studies. Case-control studies containing available genotype frequencies of IL-6 -174G/C were chosen, and odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of this association.

RESULTSA total of seven studies involving 6 464 subjects (knee OA 3 331 and controls 3 133) were considered in this study. The results suggested that the variant genotypes were not associated with knee OA risk in all genetic models (additive model: OR = 1.144, 95% CI 0.934-1.402, P = 0.194; recessive model: OR = 1.113, 95% CI 0.799-1.550, P = 0.526; dominant model: OR = 1.186, 95% CI 0.918-1.531, P = 0.191). A symmetric funnel plot, the Begg's test (P > 0.05), suggested that the data lacked publication bias.

CONCLUSIONSThis meta-analysis does not support the idea that rs1800795 genotype is associated with increased risk of knee OA. However, to draw comprehensive and more reliable conclusions, further prospective studies with larger numbers of participants worldwide are needed to examine the association between rs1800795 polymorphism and knee OA.

Humans ; Interleukin-6 ; genetics ; Osteoarthritis, Knee ; epidemiology ; genetics ; Polymorphism, Genetic ; genetics ; Promoter Regions, Genetic ; genetics

OBJECTIVETo study the potential transcriptional depression activities of HPV2 E2 proteins with mutations in different functional domains.

METHODSThe primers for constructing various E2 mutants were synthesized based on a HPV2 isolate containing several point mutations within E2 open reading frame. Different E2 mutations were generated by the method of extending PCR and inserted into plasmid pcDNA3. 1. Various recombinant mammalian expression plasmids pcDNA3. 1-E2 were co-transfected into HeLa cells together with a CAT-reporter plasmid pBLCAT-LCR containing HPV-2 prototype LCR, respectively. The transcriptional repression activities of the E2 mutants were evaluated by detection of CAT expression values.

RESULTSCompared with the full-length prototype E2, removals of both N- and C-terminal domains abolished E2 transcriptional repressive activities. The point mutations in the transactivation domain (nt 3037), the internal hinge region (nt 3387) and DNA binding domain (nt 3697) showed remarkable inhibition on its transcriptional depression function.

CONCLUSIONThe transcriptional regulation activity of HPV2 E2 is related with its DNA binding and transactivation domains. The exchanges of the single amino acid within E2, derived from a HPV2 isolate, abolish significantly the repressive effect on viral promoter in the context of full-length E2.

HeLa Cells ; Humans ; Oncogene Proteins, Viral ; genetics ; Papillomaviridae ; genetics ; Promoter Regions, Genetic ; genetics ; Transcriptional Activation ; genetics

ObjectiveThe objective of the study was to summarize the role of DNA methylation in the development and metastasis of uveal melanoma (UM).

Data SourcesThe relevant studies in MEDLINE were searched.

Study SelectionIn this review, we performed a comprehensive literature search in MEDLINE using "uveal melanoma" AND ("DNA methylation" OR "epigenetics") for original research/review articles published before February 2018 on the relationship between DNA methylation and UM. References of the retrieved studies were also examined to search for potentially relevant papers.

ResultsPrevious studies on the relationship between DNA methylation and UM covered many genes including tumor suppressor genes (TSGs), cyclin-dependent kinase genes, and other genes. Among them, the TSG genes such as RASSF1A and p16INK4a, which encodes a cyclin-dependent kinase inhibitor, are relatively well-studied genes. Specifically, a high percentage of promoter methylation of RASSF1A was observed in UM cell lines and/or patients with UM. Promoter methylation of RASSF1A was also associated with the development of metastasis. Similarly, a high percentage of promoter hypermethylation of p16INK4a was found in UM cell lines. DNA promoter methylation can control the expression of p16INK4a, which affect cell growth, migration, and invasion in UM. Many other genes might also be involved in the pathogenesis of UM such as the Ras and EF-hand domain containing (RASEF) gene, RAB31, hTERT, embryonal fyn-associated substrate, and deleted in split-hand/split-foot 1.

ConclusionsOur review reveals the complex mechanisms underlying the tumorigenesis of UM and highlights the great needs of future studies to discover more genes/5'-C-phosphate-G-3' sites contributing to the development/metastasis of UM and explore the mechanisms through which epigenetic changes exert their function in UM.

Cell Transformation, Neoplastic ; genetics ; DNA Methylation ; genetics ; Epigenesis, Genetic ; genetics ; Humans ; Melanoma ; genetics ; Promoter Regions, Genetic ; genetics ; Uveal Neoplasms ; genetics

Vitamin E (Tocopherols) is lipid-soluble antioxidants and essential for human health. Gamma-tocopherol methyltransferase (delta-TMT), one of the key enzymes in tocopherol biosynthetic pathway in plants, converts delta,sigma-tocopherols into alpha,beta-tocopherols. In this study, we isolated the 1552 bp promoter of Arabidopsis TMT gene. The promoter was fused with GUS reporter gene and this expression cassette was introduced into wild Arabidopsis thaliana by Agrobacterium-mediated transformation. GUS staining shows that GUS gene is expressed in leaves, stems and flowers, with the highest expression in young leaves, stamens and stem apices, while not observable in roots, seeds and siliques. The data indicate that gamma-TMT gene promoter is likely to be expressed preferentially in some of the tissues of Arabidopsis.
Arabidopsis ; genetics ; Base Sequence ; Genes, Reporter ; Immunohistochemistry ; Methyltransferases ; genetics ; Molecular Sequence Data ; Promoter Regions, Genetic ; genetics

OBJECTIVETo explore the mechanism of PTEN gene expression silence in leukemia cells, and the effect of induced PTEN gene expression in leukemia cells.

METHODSMethylation status of PTEN in leukemic cell lines, including HL-60, Nalm-6, NB4, U937, Raji, K562 and KG-1a was assessed by methylation specific PCR (MSP). The cell lines were then treated with different concentrations of methyltransferase inhibitor 5-Aza-2'-deoxycytidine (5-Aza-CdR). After that the changes in PTEN methylation status were detected by MSP, and PTEN mRNA expression level by reverse transcription PCR (RT-PCR). Growth inhibition and apoptosis of HL-60 and Nalm-6 cells induced by 5-Aza-CdR were observed by MTT assay, and Wright and Annexin V staining, respectively.

RESULTSHypermethylation of PTEN promoter was detected in HL-60, U937, Nalm-6, Raji and KG-1a, while hypomethylation was found in NB4 and K562 by MSP. After 5-Aza-CdR treatment, the hypermethylation status of PTEN promoter in HL-60 and Nalm-6 cells was reversed and their PTEN mRNA expression levels were up regulated in dose dependent manner with the 5-Aza-CdR concentrations, and the cell apoptosis was induced.

CONCLUSIONHypermethylation in the promoter region is one of major mechanisms responsible for transcriptional suppression of PTEN. Methyltransferase inhibitor could induce the expression of PTEN gene and lead to the leukemia cells apoptosis.

Cell Line, Tumor ; DNA Methylation ; Humans ; Leukemia ; genetics ; PTEN Phosphohydrolase ; genetics ; Promoter Regions, Genetic ; genetics

In this study the MTP1 gene, encoding a type III integral transmembrane protein, was isolated from the rice blast fungus Magnaporthe oryzae. The Mtp1 protein is 520 amino acids long and is comparable to the Ytp1 protein of Saccharomyces cerevisiae with 46% sequence similarity. Prediction programs and MTP1-GFP (green fluorescent protein) fusion expression results indicate that Mtp1 is a protein located at several membranes in the cytoplasm. The functions of the MTP1 gene in the growth and development of the fungus were studied using an MTP1 gene knockout mutant. The MTP1 gene was primarily expressed at the hyphal and conidial stages and is necessary for conidiation and conidial germination, but is not required for pathogenicity. The Deltamtp1 mutant grew more efficiently than the wild type strain on non-fermentable carbon sources, implying that the MTP1 gene has a unique role in respiratory growth and carbon source use.
Fungal Proteins ; genetics ; physiology ; Genes, Fungal ; Magnaporthe ; genetics ; Membrane Proteins ; genetics ; Oryza ; microbiology ; Promoter Regions, Genetic

OBJECTIVETo study the transcriptional regulation of human delta globin gene with C-->T point mutation at -64 in its promoter.

METHODSHuman delta globin genes including wild CAAT box and mutant CAAT box (-64C-->T) were separately cloned into eukaryotic expression vector pcDNA3.1 (-)/Myc-His A which was cut out the strong promoter CMV, transfected MEL cells, and induced by DMSO to express. The transcriptional regulation of human delta globin gene was analysed using semi-quantitative RT-PCR.

RESULTSThe expression level of human delta globin gene with mutant CAAT box was 2.2-fold as high as that with wild CAAT box.

CONCLUSIONThe defective CAAT box of human delta globin gene promoter region may be one of the major reasons for its low expression level.

CCAAT-Enhancer-Binding Proteins ; genetics ; Globins ; genetics ; Humans ; Point Mutation ; Promoter Regions, Genetic ; genetics ; Transcription, Genetic

Bacillus subtilis is a model strain for studying the physiological and biochemical mechanisms of microorganism, and is also a good chassis cell for industrial application to produce biological agents such as small molecule compounds, bulk chemicals, industrial enzymes, precursors of drugs and health product. In recent years, studies on metabolic engineering methods and strategies of B. subtilis have been increasingly reported, providing good tools and theoretical references for using it as chassis cells to produce biological agents. This review provides information on systematically optimizing the Bacillus subtilis chassis cell by regulating global regulatory factors, simplifying and optimizing the genome, multi-site and multi-dimensional regulating, dynamic regulating through biosensors, membrane protein engineering. For producing the protein reagent, the strain is optimized by optimizing the promoters, signal peptides, secretion components and building the expression system without chemical inducers. In addition, this review also prospects the important issues and directions that need to be focused on in the further optimization of B. subtilis in industrial production.
Bacillus subtilis/genetics* ; Bacterial Proteins/genetics* ; Biotechnology ; Metabolic Engineering ; Promoter Regions, Genetic ; Protein Sorting Signals/genetics*