The ubiquitous sliding clamp facilitates processivity of the replicative polymerase and acts as a platform to recruit proteins involved in replication, recombination and repair. While the dynamics of the E. coli β2-sliding clamp have been characterized in vitro, its in vivo stoichiometry and dynamics remain unclear. To probe both β2-clamp dynamics and stoichiometry in live E. coli cells, we use custom-built microfluidics in combination with single-molecule fluorescence microscopy and photoactivated fluorescence microscopy. We quantify the recruitment, binding and turnover of β2-sliding clamps on DNA during replication. These quantitative in vivo results demonstrate that numerous β2-clamps in E. coli remain on the DNA behind the replication fork for a protracted period of time, allowing them to form a docking platform for other enzymes involved in DNA metabolism.
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http://dx.doi.org/10.1038/ncomms6820 | DOI Listing |
J Physiol
January 2025
Heart Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.
Although the corticosteroid betamethasone is routinely administered to accelerate lung and cardiovascular maturation in the preterm fetus prior to birth, and use of delayed cord clamping (DCC) is recommended at birth by professional bodies, it is unknown whether antenatal betamethasone alters perinatal pulmonary or systemic arterial blood flow accompaniments of DCC. To address this issue, preterm fetal lambs [gestation 127 (1) days, term = 147 days] with (n = 10) or without (n = 10) antenatal betamethasone treatment were acutely instrumented under general anaesthesia with flow probes to obtain left (LV) and right ventricular (RV) outputs, major central arterial blood flows and shunt flow across both the ductus arteriosus and foramen ovale (FO). After delivery, lambs underwent initial ventilation for 2 min prior to DCC.
View Article and Find Full Text PDFBMC Pediatr
January 2025
Department of Orthopedics, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, No.56, Nanlishi Road, Beijing, 100045, China.
Background: Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder affecting multiple systems. However, arterial stenosis is a rare manifestation in patients with NF1. Since the symptoms of arterial stenosis caused by NF1 are often atypical and have a high under-diagnosis rate, this can lead to serious complications such as hypertension, ischemic stroke, or even death.
View Article and Find Full Text PDFLancet
January 2025
NHMRC Clinical Trials Centre, University of Sydney, Sydney, NSW 2050, Australia.
Lancet
January 2025
Department of Obstetrics and Gynecology, Monash University, Clayton, VIC 3800, Australia; Aberdeen Centre for Women's Health Research, School of Medicine, University of Aberdeen, Aberdeen, UK. Electronic address:
J Biol Chem
January 2025
Department of Chemistry and Biochemistry, Baylor University, Waco, Texas, 76798-7348, USA. Electronic address:
Coupling interactions between the alpha (α) subunit of the polymerase III core (α-Pol III core) and the tau (τ) subunit of the clamp loader complex (τ-CLC) are vital for efficient and rapid DNA replication in Escherichia coli (E. coli). Specific and targeted mutations in the C-terminal τ-interaction region of the Pol III α-subunit disrupted efficient coupled rolling circle DNA synthesis in vitro and caused significant genomic defects in CRISPR-Cas9 dnaE edited cell strains.
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