The Streptomyces coelicolor rpoC gene, that encodes the beta' subunit of RNA polymerase, was isolated using the Escherichia coli rpoC gene as a hybridization probe. Comparison of the predicted amino acid sequence of the S. coelicolor beta' subunit to those characterized from other bacteria revealed three distinct subfamilies of beta' subunits, one of which consists of the S. coelicolor subunit and those from Mycobacterium leprae and Mycoplasma genitalium. Using site-directed mutagenesis, the carboxy terminus of the S. coelicolor beta' subunit was modified to contain six histidine residues. The histidine-tagged gene, rpoCHIS, was used to replace the wild-type allele in the chromosome of S. coelicolor and S. lividans. These strains were unaffected in growth and sporulation, demonstrating that the histidine-tagged RNA polymerase was competent to carry out all essential in-vivo functions. During a 1-day procedure, highly purified RNA polymerase was obtained by nickel-NTA agarose affinity chromatography followed by heparin-sepharose chromatography. Using in-vitro run-off transcription assays, the affinity purified RNA polymerase was shown to initiate transcription correctly from the S. lividans galP1 and galP2 promoters, and the Bacillus subtilus veg and ctc promoters. An extension of this procedure yielded highly-purified core RNA polymerase. To facilitate introduction of the rpoCHIS allele into other genetic backgrounds, a mutation in the adjacent gene, rpoB (rifA), conferring rifampin-resistance, was isolated in S. coelicolor to provide a genetic marker to follow transfer of the rpoCHIS allele. The use of this affinity chromatography procedure, in combination with the ability to introduce the rpoCHIS allele into different Streptomyces strains by transformation, will greatly facilitate the in-vitro analysis of transcription in members of this genus.
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http://dx.doi.org/10.1016/s0378-1119(97)00179-0 | DOI Listing |
BMC Gastroenterol
January 2025
Department of Pediatrics, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710061, China.
Background: The increased apoptosis of bile duct epithelial cells (BECs) due to some damage factors is considered the initiating factor in the occurrence and progression of biliary atresia (BA). Vitamin D receptor (VDR) is thought to play a crucial role in maintaining the intrinsic immune balance and integrity of bile duct epithelial cells (BECs). To investigate the role of VDRs in the pathogenesis and progression of BA using in vitro and in vivo models.
View Article and Find Full Text PDFMol Biol Rep
January 2025
Department of Clinical Pathology, Faculty of Medicine, Alexandria University, Alexandria, Egypt.
Background: The identification of circulating potential biomarkers may help earlier diagnosis of breast cancer, which is critical for effective treatment and better disease outcomes. We aimed to study the role of circ-FAF1 as a diagnostic biomarker in female breast cancer using peripheral blood samples of these patients, and to investigate the relation between circ-FAF1 and different clinicopathological features of the included patients.
Methods And Results: This case-control study enrolled 60 female breast cancer patients and 60 age-matched healthy control subjects.
Spectrochim Acta A Mol Biomol Spectrosc
January 2025
CICS-UBI - Health Sciences Research Centre University of Beira Interior Covilhã Portugal; RISE-Health, Departamento de Química, Faculdade de Ciências, Universidade da Beira Interior, Rua Marquês d'Ávila e Bolama 6201-001 Covilhã, Portugal; Departamento de Química, Universidade da Beira Interior, Rua Marquês de Ávila e Bolama 6201-001 Covilhã, Portugal. Electronic address:
Rapid, quantitative, and sensitive detection of viral oligonucleotides can help to diagnose the infection before symptoms occur, monitor disease progression, and identify viral subtypes. A one-pot, simple, rapid hairpin-mediated nicking enzymatic signal amplification (HNESA) method was previously developed for nucleic acids detection. In the present work, this method was applied for the detection of SARS-CoV-2 RNA by designing an assistant probe (AP) that contains the complementary sequence for the target, the sequence of hybridization with the loop region of the molecular beacon (MB), and the recognition site of the nicking endonuclease Nt.
View Article and Find Full Text PDFBioorg Chem
January 2025
Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy (Girls), Al-Azhar University, Cairo 11754 Egypt. Electronic address:
Anti-infective agents are a class of drugs used to prevent, treat, or control infections caused by microorganisms such as bacteria, viruses, fungi, and parasites. They play a crucial role in modern medicine, helping to reduce the severity of infections and, in many cases, save lives. This study aims at the design and synthesis of hybrid compounds containing quinoxaline, pyrrolidine, and an azo bridge to combat antimicrobial resistance, and evaluating their antimicrobial, antifungal, and antiviral activities against various pathogenic strains.
View Article and Find Full Text PDFJ Vis Exp
January 2025
Institute of Biochemistry and Molecular Biology, Hengyang Medical School, University of South China; National Health Commission Key Laboratory of Birth Defect Research and Preventio, Hunan Provincial Maternal and Child Health Care Hospital;
Both DNA replication and RNA transcription utilize genomic DNA as their template, necessitating spatial and temporal separation of these processes. Conflicts between the replication and transcription machinery, termed transcription-replication conflicts (TRCs), pose a considerable risk to genome stability, a critical factor in cancer development. While several factors regulating these collisions have been identified, pinpointing primary causes remains difficult due to limited tools for direct visualization and clear interpretation.
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