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Abstract Natural transformation, the process whereby a cell acquires DNA directly from the environment, is an important driver of evolution in microbial populations, yet the mechanism of DNA uptake is only characterized in bacteria. To expand our understanding of natural transformation in archaea, we undertook a genetic approach to identify a catalog of genes necessary for transformation inMethanococcus maripaludis. Using an optimized method to generate random transposon mutants, we screened 6144 mutant strains for defects in natural transformation and identified 25 transformation-associated candidate genes. Among these are genes encoding components of the type IV-like pilus, transcription/translation associated genes, genes encoding putative membrane bound transport proteins, and genes of unknown function. Interestingly, similar genes were identified regardless of whether replicating or integrating plasmids were provided as a substrate for transformation. Using allelic replacement mutagenesis, we confirmed that several genes identified in these screens are essential for transformation. Finally, we identified a homolog of a membrane bound substrate transporter inMethanoculleus thermophilusand verified its importance for transformation using allelic replacement mutagenesis, suggesting a conserved mechanism for DNA transfer in multiple archaea. These data represent an initial characterization of the genes important for transformation which will inform efforts to understand gene flow in natural populations. Additionally, knowledge of the genes necessary for natural transformation may assist in identifying signatures of transformation machinery in archaeal genomes and aid the establishment of new model genetic systems for studying archaea.
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The circadian clock and darkness control natural competence in cyanobacteria
Abstract The cyanobacteriumSynechococcus elongatusis a model organism for the study of circadian rhythms. It is naturally competent for transformation—that is, it takes up DNA from the environment, but the underlying mechanisms are unclear. Here, we use a genome-wide screen to identify genes required for natural transformation inS. elongatus, including genes encoding a conserved Type IV pilus, genes known to be associated with competence in other bacteria, and others. Pilus biogenesis occurs daily in the morning, while natural transformation is maximal when the onset of darkness coincides with the dusk circadian peak. Thus, the competence state in cyanobacteria is regulated by the circadian clock and can adapt to seasonal changes of day length.
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- Award ID(s):
- 1754946
- PAR ID:
- 10153812
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 11
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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