Given the success of the previous Research Topics, we would like to revisit this topic with a third edition. DNA replication, a central event for cell proliferation, is the basis of biological inheritance. Complete and accurate DNA replication is integral to the maintenance of the genetic integrity of organisms. In all three domains of life, DNA replication begins at replication origins. In bacteria, replication typically initiates from a single replication origin (oriC), which contains several DnaA boxes and the AT-rich DNA unwinding element (DUE). Recently, DnaA-trio has been discovered and characterized as a novel bacterial oriC element. In eukaryotic genomes, replication initiates from significantly more replication origins, activated simultaneously at a specific time. For eukaryotic organisms, replication origins are best characterized in the unicellular eukaryote budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe. The budding yeast origins contain an essential sequence element called the ARS (autonomously replicating sequence), while the fission yeast origins consist of AT-rich sequences. Within the archaeal domain, the multiple replication origins have been identified by a predict-and-verify approach in the hyperthermophilic archaeon Sulfolobus. The basic structure of replication origins is conserved among archaea, typically including an AT-rich unwinding region flanked by several short repetitive DNA sequences, known as origin recognition boxes (ORBs). It appears that archaea have a simplified version of the eukaryotic replication apparatus, which has led to considerable interest in the archaeal machinery as a model of that in eukaryotes.

The research on replication origins is important not only in providing insights into the structure and function of the replication origins but also in understanding the regulatory mechanisms of the initiation step in DNA replication. Therefore, intensive studies have been carried out in the last two decades. Based on the sequence-derived features, various in silico approaches have been developed to identify microbial replication origins. In comparison with the in silico analysis, the experimental methods are time-consuming and labor-intensive, but convincing and reliable. A number of experimental methods have been used to identify and characterize microbial replication origins in vivo or in vitro. In addition, the availability of increasing complete microbial genomes and emerging approaches has created challenges and opportunities for identification and characterization of microbial replication origins in silico, as well as in vivo and in vitro.

This Research Topic is devoted to provide a comprehensive overview of DNA replication origins in microbial genomes, and we welcome the submissions of original research articles, reviews, min-reviews, methods article, perspective, and opinions that make a substantial and updated contribution to this field.

Take a look at the previous editions of this Research Topic here:

DNA Replication Origins in Microbial Genomes

DNA Replication Origins in Microbial Genomes, Volume II

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DNA Replication Origins in Microbial Genomes, Volume III