scholarly journals Rns regulates nonpilus adhesin EtpA in human EnterotoxigenicE.coli(ETEC)

2018 ◽  
Author(s):  
T.P.Vipin Madhavan

AbstractRns, an araC family of transcriptional activator (AFTR) is known to regulate many of the known pili in human ETEC. Apart from pili, Rns is also known to regulate some nonpilus genes believed to have role in virulence. EtpA is a nonpilus adhesin, encoded with inetpBACoperon in ETEC genome. Using a combination of qRT-PCR and gel shift assay, we show that Rns binds to upstream of etpBAC operon and upregulates the expression of EtpA. This is the first report of Rns regulating a known virulence factor in ETEC.

1998 ◽  
Vol 42 (2) ◽  
pp. 93-96
Author(s):  
Takumi Kawabe ◽  
Toshifumi Tetsuka ◽  
Takashi Okamoto

2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Yong Feng ◽  
Yunfei Liao ◽  
Jianming Zhang ◽  
Jacson Shen ◽  
Zengwu Shao ◽  
...  

Abstract Background Aberrant expression of cyclin-dependent protein kinases (CDK) is a hallmark of cancer. CDK11 plays a crucial role in cancer cell growth and proliferation. However, the molecular mechanisms of CDK11 and CDK11 transcriptionally regulated genes are largely unknown. Methods In this study, we performed a global transcriptional analysis using gene array technology to investigate the transcriptional role of CDK11 in osteosarcoma. The promoter luciferase assay, chromatin immunoprecipitation assay, and Gel Shift assay were used to identify direct transcriptional targets of CDK11. Clinical relevance and function of core-binding factor subunit beta (CBFβ) were further accessed in osteosarcoma. Results We identified a transcriptional role of protein-DNA interaction for CDK11p110, but not CDK11p58, in the regulation of CBFβ expression in osteosarcoma cells. The CBFβ promoter luciferase assay, chromatin immunoprecipitation assay, and Gel Shift assay confirmed that CBFβ is a direct transcriptional target of CDK11. High expression of CBFβ is associated with poor outcome in osteosarcoma patients. Expression of CBFβ contributes to the proliferation and metastatic behavior of osteosarcoma cells. Conclusions These data establish CBFβ as a mediator of CDK11p110 dependent oncogenesis and suggest that targeting the CDK11- CBFβ pathway may be a promising therapeutic strategy for osteosarcoma treatment. Graphical Abstract


2002 ◽  
Vol 70 (4) ◽  
pp. 2238-2241 ◽  
Author(s):  
Atanas Ignatov ◽  
Elizabeth J. Keath

ABSTRACT A gel shift assay was optimized to detect several general DNA binding proteins from Histoplasma capsulatum strain G217B. The electrophoretic mobility shift assay (EMSA) technique also detected protein(s) recognizing a pyrimidine-rich motif found in several Histoplasma promoters. Establishment of EMSA conditions provides an important framework to evaluate regulation of homeostatic or phase-specific genes that may influence virulence in Histoplasma and other dimorphic fungal pathogens.


1994 ◽  
Vol 165 (2) ◽  
pp. 627-638 ◽  
Author(s):  
Valérie Mezger ◽  
Jean-Paul Renard ◽  
Elisabeth Christians ◽  
Michel Morange

2000 ◽  
Vol 182 (2) ◽  
pp. 529-531 ◽  
Author(s):  
Nicholas H. Carbonetti ◽  
Alla Romashko ◽  
Teresa J. Irish

ABSTRACT Overexpression of the RNA polymerase alpha subunit inBordetella pertussis reduces expression of the virulence factor pertussis toxin. Here we show that this reduction is at the level of transcription, is reversed by overexpression of the transcriptional activator BvgA, and is dependent on the C-terminal domain of alpha.


1999 ◽  
Vol 181 (8) ◽  
pp. 2338-2345 ◽  
Author(s):  
J. S. Hwang ◽  
J. Yang ◽  
A. J. Pittard

ABSTRACT In the presence of tyrosine, the TyrR protein of Escherichia coli represses the expression of the tyrP gene by binding to the double TyrR boxes which overlap the promoter. Previously, we have carried out methylation, uracil, and ethylation interference experiments and have identified both guanine and thymine bases and phosphates within the TyrR box sequences that are contacted by the TyrR protein (J. S. Hwang, J. Yang, and A. J. Pittard, J. Bacteriol. 179:1051–1058, 1997). In this study, we have used missing contact probing to test the involvement of all of the bases within the tyrP operator in the binding of TyrR. Our results indicate that nearly all the bases within the palindromic arms of the strong and weak boxes are important for the binding of the TyrR protein. Two alanine-substituted mutant TyrR proteins, HA494 and TA495, were purified, and their binding affinities for the tyrP operator were measured by a gel shift assay. HA494 was shown to be completely defective in binding to the tyrP operator in vitro, while, in comparison with wild-Type TyrR, TA495 had only a small reduction in DNA binding. Missing contact probing was performed by using the purified TA495 protein, and the results suggest that T495 makes specific contacts with adenine and thymine bases at the ±5 positions in the TyrR boxes.


1990 ◽  
Vol 10 (8) ◽  
pp. 3884-3895 ◽  
Author(s):  
R M Luche ◽  
R Sumrada ◽  
T G Cooper

Induction of the arginase (CAR1) gene expression in Saccharomyces cerevisiae has previously been shown to require participation of a cis-dominantly regulated upstream repression sequence (URS). Deletion of this element results in high-level expression of the CAR1 gene without inducer. To determine the structure of the CAR1 URS element, we performed a saturation mutagenesis. Results of the mutagenic analysis indicated that the CAR1 URS was a 9-base-pair palindromic sequence, 5'-AGCCGCCGA-3'. A DNA fragment containing this sequence was shown to bind one or more proteins by a gel shift assay. DNA fragments containing point mutations that completely eliminated URS function were not effective competitors in this assay, whereas those which supported URS function were effective competitors. Sequences in the 5'-flanking regions of 14 other genes were found to be homologous to the CAR1 URS. These sequences were shown to support varying degrees of URS function in the expression vector assay, to bind protein as demonstrated by the gel shift assay, and to compete with a DNA fragment containing the CAR1 URS for protein binding. These results indicate that the CAR1 URS element possesses the characteristics of a repressor binding site. Further, they are consistent with the suggestion that sites homologous to the CAR1 URS may be situated in the 5'-flanking regions of multiple unrelated yeast genes. The widespread occurrence of this element raises the possibility that it is the target site for one or more negatively acting general transcription factors.


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