E1A 13S and 12S mRNA products made in Escherichia coli both function as nucleus-localized transcription activators but do not directly bind DNA

1985 ◽  
Vol 5 (10) ◽  
pp. 2653-2661
Author(s):  
B Ferguson ◽  
B Krippl ◽  
O Andrisani ◽  
N Jones ◽  
H Westphal ◽  
...  

We previously purified and characterized functionally the Escherichia coli-expressed product of the human subgroup C adenovirus E1A 13S mRNA (B. Ferguson, N. Jones, J. Richter, and M. Rosenberg, Science 224:1343-1346, 1984; B. Krippl, B. Ferguson, M. Rosenberg, and H. Westphal, Proc. Natl. Acad. Sci. USA 81:6988-6992, 1984). We have now expressed in E. coli and purified the protein product encoded by the human subgroup C adenovirus E1A 12S mRNA and have compared the functional properties of this protein with those of the E1A 13S mRNA product. Using microinjection techniques to introduce these proteins into mammalian cells, we found that the E1A 12S mRNA product, like the 13S mRNA product, localized rapidly to the cell nucleus and induced adenovirus gene expression. Although both E1A gene products localized to the nucleus and stimulated adenovirus gene transcription, these proteins did not directly bind to DNA under conditions in which a known DNA-binding protein, the human c-myc gene product, bound DNA efficiently. Thus, the E1A and myc gene products, which have been related both structurally and functionally, exhibit distinctly different biochemical properties.

1985 ◽  
Vol 5 (10) ◽  
pp. 2653-2661 ◽  
Author(s):  
B Ferguson ◽  
B Krippl ◽  
O Andrisani ◽  
N Jones ◽  
H Westphal ◽  
...  

We previously purified and characterized functionally the Escherichia coli-expressed product of the human subgroup C adenovirus E1A 13S mRNA (B. Ferguson, N. Jones, J. Richter, and M. Rosenberg, Science 224:1343-1346, 1984; B. Krippl, B. Ferguson, M. Rosenberg, and H. Westphal, Proc. Natl. Acad. Sci. USA 81:6988-6992, 1984). We have now expressed in E. coli and purified the protein product encoded by the human subgroup C adenovirus E1A 12S mRNA and have compared the functional properties of this protein with those of the E1A 13S mRNA product. Using microinjection techniques to introduce these proteins into mammalian cells, we found that the E1A 12S mRNA product, like the 13S mRNA product, localized rapidly to the cell nucleus and induced adenovirus gene expression. Although both E1A gene products localized to the nucleus and stimulated adenovirus gene transcription, these proteins did not directly bind to DNA under conditions in which a known DNA-binding protein, the human c-myc gene product, bound DNA efficiently. Thus, the E1A and myc gene products, which have been related both structurally and functionally, exhibit distinctly different biochemical properties.


Microbiology ◽  
2005 ◽  
Vol 151 (5) ◽  
pp. 1421-1431 ◽  
Author(s):  
Patrice Bruscella ◽  
Laure Cassagnaud ◽  
Jeanine Ratouchniak ◽  
Gaël Brasseur ◽  
Elisabeth Lojou ◽  
...  

The gene encoding a putative high-potential iron–sulfur protein (HiPIP) from the strictly acidophilic and chemolithoautotrophic Acidithiobacillus ferrooxidans ATCC 33020 has been cloned and sequenced. This potential HiPIP was overproduced in the periplasm of the neutrophile and heterotroph Escherichia coli. As shown by optical and EPR spectra and by electrochemical studies, the recombinant protein has all the biochemical properties of a HiPIP, indicating that the iron–sulfur cluster was correctly inserted. Translocation of this protein in the periplasm of E. coli was not detected in a ΔtatC mutant, indicating that it is dependent on the Tat system. The genetic organization of the iro locus in strains ATCC 23270 and ATCC 33020 is different from that found in strains Fe-1 and BRGM. Indeed, in A. ferrooxidans ATCC 33020 and ATCC 23270 (the type strain), iro was not located downstream from purA but was instead downstream from petC2, encoding cytochrome c 1 from the second A. ferrooxidans cytochrome bc 1 complex. These findings underline the genotypic heterogeneity within the A. ferrooxidans species. The results suggest that Iro transfers electrons from a cytochrome bc 1 complex to a terminal oxidase, as proposed for the HiPIP in photosynthetic bacteria.


Author(s):  
Rogayeh Nouri ◽  
Alka Hasani ◽  
Kourosh Masnadi Shirazi ◽  
Mohammad Reza Aliand ◽  
Bita Sepehri ◽  
...  

: Colorectal cancer (CRC) is one of the deadliest cancers in the world. Specific strains of intestinal Escherichia coli (E. coli) may influence the initiation and development of CRC by exploiting virulence factors and inflammatory pathways. Mucosa-associated E. coli strains are more prevalent in CRC biopsies in comparison to healthy controls. Moreover, these strains can survive and replicate within macrophages and induce a pro-inflammatory response. Chronic exposure to inflammatory mediators can lead to increased cell proliferation and cancer. Production of colobactin toxin by the majority of mucosa-associated E. coli isolated from CRC patients is another notable finding. Colibactin-producing E. coli strains, in particular, induce double-strand DNA breaks, stop the cell cycle, involve in chromosomal rearrangements of mammalian cells and are implicated in carcinogenic effects in animal models. Moreover, some enteropathogenic E. coli (EPEC) strains are able to survive and replicate in colon cells as chronic intracellular pathogens and may promote susceptibility to CRC by downregulation of DNA Mismatch Repair (MMR) proteins. In this review, we discuss current evidence and focus on the mechanisms by which E. coli can influence the development of CRC.


Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 420 ◽  
Author(s):  
Mst. Sonia Parvin ◽  
Sudipta Talukder ◽  
Md. Yamin Ali ◽  
Emdadul Haque Chowdhury ◽  
Md. Tanvir Rahman ◽  
...  

Escherichia coli is known as one of the most important foodborne pathogens in humans, and contaminated chicken meat is an important source of foodborne infection with this bacterium. The occurrence of extended-spectrum β-lactamase (ESBL)-producing E. coli (ESBL-Ec), in particular, in chicken meat is considered a global health problem. This study aimed to determine the magnitude of E. coli, with special emphasis on ESBL-Ec, along with their phenotypic antimicrobial resistance pattern in frozen chicken meat. The study also focused on the determination of ESBL-encoding genes in E. coli. A total of 113 frozen chicken meat samples were purchased from 40 outlets of nine branded supershops in five megacities in Bangladesh. Isolation and identification of E. coli were done based on cultural and biochemical properties, as well as PCR assay. The resistance pattern was determined by the disc diffusion method. ESBL-encoding genes were determined by multiplex PCR. The results showed that 76.1% of samples were positive for E. coli, of which 86% were ESBL producers. All the isolates were multidrug-resistant (MDR). Resistance to 9–11 and 12–13 antimicrobial classes was observed in 38.4% and 17.4% isolates, respectively, while only 11.6% were resistant to 3–5 classes. Possible extensive drug resistance (pXDR) was found in 2.3% of isolates. High single resistance was observed for oxytetracycline (93%) and amoxicillin (91.9%), followed by ampicillin (89.5%), trimethoprim–sulfamethoxazole, and pefloxacin (88.4%), and tetracycline (84.9%). Most importantly, 89.6% of isolates were resistant to carbapenems. All the isolates were positive for the blaTEM gene. However, the blaSHV and blaCTX-M-2 genes were identified in two ESBL-non producer isolates. None of the isolates carried the blaCTX-M-1 gene. This study provided evidence of the existence of MDR and pXDR ESBL-Ec in frozen chicken meat in Bangladesh, which may pose a risk to human health if the meat is not properly cooked or pickled raw only. This emphasizes the importance of the implementation of good slaughtering and processing practices by the processors.


2004 ◽  
Vol 186 (23) ◽  
pp. 8058-8065 ◽  
Author(s):  
Orla Sherlock ◽  
Mark A. Schembri ◽  
Andreas Reisner ◽  
Per Klemm

ABSTRACT Diarrhea-causing Escherichia coli strains are responsible for numerous cases of gastrointestinal disease and constitute a serious health problem throughout the world. The ability to recognize and attach to host intestinal surfaces is an essential step in the pathogenesis of such strains. AIDA is a potent bacterial adhesin associated with some diarrheagenic E. coli strains. AIDA mediates bacterial attachment to a broad variety of human and other mammalian cells. It is a surface-displayed autotransporter protein and belongs to the selected group of bacterial glycoproteins; only the glycosylated form binds to mammalian cells. Here, we show that AIDA possesses self-association characteristics and can mediate autoaggregation of E. coli cells. We demonstrate that intercellular AIDA-AIDA interaction is responsible for bacterial autoaggregation. Interestingly, AIDA-expressing cells can interact with antigen 43 (Ag43)-expressing cells, which is indicative of an intercellular AIDA-Ag43 interaction. Additionally, AIDA expression dramatically enhances biofilm formation by E. coli on abiotic surfaces in flow chambers.


2007 ◽  
Vol 189 (11) ◽  
pp. 4325-4327 ◽  
Author(s):  
Sarah E. Broadbent ◽  
Roberto Balbontin ◽  
Josep Casadesus ◽  
Martin G. Marinus ◽  
Marjan van der Woude

ABSTRACT The Caulobacter crescentus DNA adenine methyltransferase CcrM and its homologs in the α-Proteobacteria are essential for viability. CcrM is 34% identical to the yhdJ gene products of Escherichia coli and Salmonella enterica. This study provides evidence that the E. coli yhdJ gene encodes a DNA adenine methyltransferase. In contrast to an earlier report, however, we show that yhdJ is not an essential gene in either E. coli or S. enterica.


1996 ◽  
Vol 16 (3) ◽  
pp. 907-913 ◽  
Author(s):  
H J Drabkin ◽  
H J Park ◽  
U L RajBhandary

As an approach to inducible suppression of nonsense mutations in mammalian and in higher eukaryotic cells, we have analyzed the expression of an Escherichia coli glutamine-inserting amber suppressor tRNA gene in COS-1 and CV-1 monkey kidney cells. The tRNA gene used has the suppressor tRNA coding sequence flanked by sequences derived from a human initiator methionine tRNA gene and has two changes in the coding sequence. This tRNA gene is transcribed, and the transcript is processed to yield the mature tRNA in COS-1 and CV-1 cells. We show that the tRNA is not aminoacylated in COS-1 cells by any of the endogenous aminoacyl-tRNA synthetases and is therefore not functional as a suppressor. Concomitant expression of the E. coli glutaminyl-tRNA synthetase gene results in aminoacylation of the suppressor tRNA and its functioning as a suppressor. These results open up the possibility of attempts at regulated suppression of nonsense codons in mammalian cells by regulating expression of the E. coli glutaminyl-tRNA synthetase gene in an inducible, cell-type specific, or developmentally regulated manner.


1972 ◽  
Vol 130 (4) ◽  
pp. 1095-1099 ◽  
Author(s):  
Vijendra K. Singh ◽  
S. C. Sung

1. Transcription of ox brain chromatin by brain nuclear RNA polymerase II and Escherichia coli RNA polymerase was studied. 2. The soluble chromatin prepared from brain nuclei contained DNA, RNA, histone and non-histone proteins. Such chromatin preparations did not display any endogenous RNA polymerase activity, when assayed in the presence of concentrations of KCl as high as 0.4m. 3. The chromatin-templated activity of brain nuclear polymerase II was stimulated by KCl, with an optimum around 0.25m. 4. The template activity of brain chromatin for brain nuclear polymerase II and E. coli enzyme was about 20–25% of that of pure DNA. This greatly repressed templatecapacity of chromatin was probably due to the acid-soluble chromosomal proteins. 5. Brain nuclear polymerase II was 3–4 times more active with dehistonized chromatin than with pure DNA as template, whereas bacterial enzyme was almost equally active with either of these two templates, reflecting the specificity of the transcriptional control mechanisms in mammalian cells.


2017 ◽  
Vol 14 (2) ◽  
pp. 289-295
Author(s):  
M. M. Islam ◽  
S. Ahamed ◽  
M. Y. Arafat ◽  
I. Hasan ◽  
M. Rahman ◽  
...  

This study was designed to determine the shiga toxin producing genes and to investigate antibiotic sensitivity or resistant patterns of the Escherichia coli isolated from diarrheic children at Mymensingh Medical College Hospital, Bangladesh. A total of 83 stool samples were collected and screened for the detection of E. coli on the basis of cultural, staining and biochemical properties followed by molecular detection by Polymerase Chain Reaction (PCR) using genus specific 16SrRNA primers. Antimicrobial susceptibility pattern of E. coli was determined by disc diffusion method against 9 antimicrobial agents. In this study, 27 (32.53%) out of 83 samples, were confirmed as E. coli. Overall prevalence of shiga toxin producing E. coli (STEC) among the examined children was 1.20% (n=1/83).  Further, 27 E. coli isolates were analyzed for the presence of Stx-1 and Stx-2 genes by duplex-PCR.  The STEC isolate was confirmed to be positive for the presence of the Stx-2 gene only. Highest susceptibility of the E. coli isolates was found against Gentamicin (92.59%), followed by Ciprofloxacin (48.14%) and Moxifloxacin (33.33%). More than 77.78% of the isolates were resistant to more than three antibiotics thus defined as multi-drug resistant (MDR). In conclusion, Gentamicin and Ciprofloxacin can be recommended as the effective drugs successful treatment of STEC infections in children.


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