Replication of vertebrate genomes is tightly regulated to ensure accurate duplication, but our understanding of the interplay between genetic and epigenetic factors in this regulation remains incomplete. Here, we investigated the involvement of three elements enriched at gene promoters and replication origins: guanine-rich motifs potentially forming G-quadruplexes (pG4s), nucleosome-free regions (NFRs), and the histone variant H2A.Z, in the firing of origins of replication in vertebrates. We show that two pG4s on the same DNA strand (dimeric pG4s) are sufficient to induce the assembly of an efficient minimal replication origin without inducing transcription in avian DT40 cells. Dimeric pG4s in replication origins are associated with formation of an NFR next to precisely-positioned nucleosomes enriched in H2A.Z on this minimal origin and genome-wide. Thus, our data suggest that dimeric pG4s are important for the organization and duplication of vertebrate genomes. It supports the hypothesis that a nucleosome close to an NFR is a shared signal for the formation of replication origins in eukaryotes.
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http://dx.doi.org/10.1038/s41467-023-40441-4 | DOI Listing |
Vet Microbiol
January 2025
Key Laboratory of Avian Bioproducts Development, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonosis, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China; Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agri-food Safety and Quality, Ministry of Agriculture of China (26116120), College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, China.
Currently, there is increasing spillover of highly pathogenic H5N1 avian influenza virus (AIV) to mammals, raising a concern of pandemic threat about this virus. Although the function of PA protein of the influenza virus is well understood, the understanding of how phosphorylation regulates this protein and influenza viral life cycle is still limited. We previously identified PA S225 as the phosphorylation site in the highly pathogenic H5N1 AIV.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Department of Chemistry, Ben-Gurion University of the Negev, Be'er Sheva 84105, Israel.
ConspectusA key challenge in modern chemistry research is to mimic life-like functions using simple molecular networks and the integration of such networks into the first functional artificial cell. Central to this endeavor is the development of signaling elements that can regulate the cell function in time and space by producing entities of code with specific information to induce downstream activity. Such artificial signaling motifs can emerge in nonequilibrium systems, exhibiting complex dynamic behavior like bistability, multistability, oscillations, and chaos.
View Article and Find Full Text PDFElife
January 2025
Translational Science and Therapeutics Division, Human Biology Division, Fred Hutchinson Cancer Center, Seattle, United States.
The association between late replication timing and low transcription rates in eukaryotic heterochromatin is well known, yet the specific mechanisms underlying this link remain uncertain. In , the histone deacetylase Sir2 is required for both transcriptional silencing and late replication at the repetitive ribosomal DNA (rDNA) arrays. We have previously reported that in the absence of , a de-repressed RNA PolII repositions MCM replicative helicases from their loading site at the ribosomal origin, where they abut well-positioned, high-occupancy nucleosomes, to an adjacent region with lower nucleosome occupancy.
View Article and Find Full Text PDFThe six subunit Origin Recognition Complex (ORC) is a DNA replication initiator that also promotes heterochromatinization in some species. A multi-omics study in a human cell line with mutations in three subunits of ORC, reveals that the subunits bind to DNA independent of each other rather than as part of a common six-subunit ORC. While DNA-bound ORC2 was seen to compact chromatin and attract repressive histone marks, the activation of chromatin and protection from repressive marks was seen at a large number of sites.
View Article and Find Full Text PDFVirology
December 2024
Virginia Commonwealth University (VCU), Philips Institute for Oral Health Research, School of Dentistry, Richmond, VA, 23298, USA; VCU Massey Cancer Center, Richmond, VA, 23298, USA.
All papillomaviruses encode an E2 protein and it is essential for the viral life cycle. E2 has three domains; a carboxyl-terminal DNA binding and dimerization domain, an amino-terminal protein interaction domain and a hinge region linking these two. Following homo-dimerization human papillomavirus E2 binds to four 12bp palindromic DNA sequences located in the non-coding long control region (LCR) of the viral genome.
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