In addition to the canonical right-handed double helix, other DNA structures, termed 'non-B DNA', can form in the genomes across the tree of life. Non-B DNA regulates multiple cellular processes, including replication and transcription, yet its presence is associated with elevated mutagenicity and genome instability. These discordant cellular roles fuel the enormous potential of non-B DNA to drive genomic and phenotypic evolution. Here we discuss recent studies establishing non-B DNA structures as novel functional elements subject to natural selection, affecting evolution of transposable elements (TEs), and specifying centromeres. By highlighting the contributions of non-B DNA to repeated evolution and adaptation to changing environments, we conclude that evolutionary analyses should include a perspective of not only DNA sequence, but also its structure.
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http://dx.doi.org/10.1016/j.tig.2022.11.005 | DOI Listing |
Nucleic Acids Res
December 2024
Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA.
Long AT repeat tracts form non-B DNA structures that stall DNA replication and cause chromosomal breakage. AT repeats are abundant in human common fragile sites (CFSs), genomic regions that undergo breakage under replication stress. Using an in vivo yeast model system containing AT-rich repetitive elements from human CFS FRA16D, we find that DNA polymerase zeta (Pol ζ) is required to prevent breakage and subsequent deletions at hairpin and cruciform forming (AT/TA)n sequences, with little to no role at an (A/T)28 repeat or a control non-structure forming sequence.
View Article and Find Full Text PDFbioRxiv
December 2024
Department of Biology, Penn State University, University Park, PA 16802, USA.
Non-canonical (non-B) DNA structures-e.g., bent DNA, hairpins, G-quadruplexes, Z-DNA, etc.
View Article and Find Full Text PDFOpen Life Sci
November 2024
The First Affiliated Hospital of Huzhou University, Hu Zhou, China.
Radiotherapy is a cornerstone in the treatment of various tumors, yet radioresistance often leads to treatment failure and tumor recurrence. Several factors contribute to this resistance, including hypoxia, DNA repair mechanisms, and cancer stem cells. This review explores the diverse elements that drive tumor radiotherapy resistance.
View Article and Find Full Text PDFGenomics Inform
November 2024
Department of Biotechnology, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Guntur, Andhra Pradesh, 522302, India.
The untranslated regions (UTRs) of genes significantly impact various biological processes, including transcription, posttranscriptional control, mRNA stability, localization, and translation efficiency. In functional areas of genomes, non-B DNA structures such as cruciform, curved, triplex, G-quadruplex, and Z-DNA structures are common and have an impact on cellular physiology. Although the role of these structures in cis-regulatory regions such as promoters is well established in eukaryotic genomes, their prevalence within UTRs across different eukaryotic classes has not been extensively documented.
View Article and Find Full Text PDFBMC Genomics
November 2024
Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, 300044, Taiwan.
Background: Z-DNA, a left-handed helical form of DNA, plays a significant role in genomic stability and gene regulation. Its formation, associated with high GC content and repetitive sequences, is linked to genomic instability, potentially leading to large-scale deletions and contributing to phenotypic diversity and evolutionary adaptation.
Results: In this study, we analyzed the density of Z-DNA-prone motifs of 154 avian genomes using the non-B DNA Motif Search Tool (nBMST).
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