DNA replication initiates at origins within the genome. The late-firing murine adenosine deaminase (mAdA) origin is located within a 2 kb fragment of DNA, making it difficult to examine by realtime technology. In this study, fine mapping of the mAdA region by measuring the abundance of nascent strand DNA identified two origins, mAdA-1 and mAdA-C, located 397 bp apart from each other. Both origins conferred autonomous replication to plasmids transfected in murine embryonic fibroblasts (MEFs), and exhibited similar activities in vivo and in vitro. Furthermore, both were able to recruit the DNA replication initiator proteins Cdc6 and Ku in vitro, similar to other bona fide replication origins. When tested in a murine Ku80(-/-) cell line, both origins exhibited replication activities comparable to those observed in wildtype cells, as did the hypoxanthine-guanine phosphoribosyltransferase (HPRT) and c-myc origins. This contrasts with previously published studies using Ku80-deficient human cells lines and suggests differences in the mechanism of initiation of DNA replication between the murine and human systems.
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Int J Biol Macromol
January 2025
Stomatological Hospital, School of Stomatology, Southern Medical University, Guangzhou 510280, Guangdong, China. Electronic address:
R-loops, three-stranded nucleic acid structures composed of RNA-DNA hybrids, are increasingly recognized as central regulators of genomic stability and transcription. These structures play critical roles across various cellular processes, including DNA replication, repair, and gene regulation, with significant implications for stem cell biology and disease pathogenesis. This review comprehensively explores the molecular underpinnings of R-loop formation, emphasizing the dual nature of R-loops in both facilitating normal cellular functions and contributing to genomic instability.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
School of Biomedical and Pharmaceutical Sciences, Guangdong University of Technology, Guangzhou 510006, China; Smart Medical Innovation Technology Center, Guangdong University of Technology, Guangzhou 510006, China. Electronic address:
G-quadruplexes (G4s) are non-canonical nucleic acid secondary structures formed by guanine-rich DNA or RNA sequences. These structures play pivotal roles in cellular processes, including DNA replication, transcription, RNA splicing, and protein translation. High-throughput sequencing has significantly advanced the study of G4s by enabling genome-wide mapping and detailed characterization.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Quantitative Biology Group, University of Belgrade - Faculty of Biology, Studentski trg 16, Belgrade11000, Serbia.
Type II restriction-modification (R-M) systems play a pivotal role in bacterial defense against invading DNA, influencing the spread of pathogenic traits. These systems often involve coordinated expression of a regulatory protein (C) with restriction (R) enzymes, employing complex feedback loops for regulation. Recent studies highlight the crucial balance between R and M enzymes in controlling horizontal gene transfer (HGT).
View Article and Find Full Text PDFFront Parasitol
March 2024
Departamento de Genética, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
Flatworms depend on stem cells for continued tissue growth and renewal during their life cycles, making these cells valuable drug targets. While neoblasts are extensively characterized in the free-living planarian , and similar stem cells have been characterized in the trematode , their identification and characterization in cestodes is just emerging. Since stem cells are generally affected by irradiation, in this work we used this experimental approach to study the stem cells of the model cestode .
View Article and Find Full Text PDFFront Antibiot
April 2024
Department of Biology, University of Copenhagen, Copenhagen, Denmark.
Initiation of chromosome replication is an essential stage of the bacterial cell cycle that is controlled by the DnaA protein. With the aim of developing novel antimicrobials, we have targeted the initiation of DNA replication, using antisense peptide nucleic acids (PNAs), directed against DnaA translation. A series of anti-DnaA PNA conjugated to lysine-rich bacterial penetrating peptides (PNA-BPPs) were designed to block DnaA translation.
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