7-Deazaguanine modifications protect phage DNA from host restriction systems.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31784519.
- Also identified by DOI 10.1038/s41467-019-13384-y and PMC identifier 6884629.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Genome modifications are central components of the continuous arms race between viruses and their hosts. The archaeosine base (G<sup>+</sup>), which was thought to be found only in archaeal tRNAs, was recently detected in genomic DNA of Enterobacteria phage 9g and was proposed to protect phage DNA from a wide variety of restriction enzymes. In this study, we identify three additional 2'-deoxy-7-deazaguanine modifications, which are all intermediates of the same pathway, in viruses: 2'-deoxy-7-amido-7-deazaguanine (dADG), 2'-deoxy-7-cyano-7-deazaguanine (dPreQ<sub>0</sub>) and 2'-deoxy-7- aminomethyl-7-deazaguanine (dPreQ<sub>1</sub>). We identify 180 phages or archaeal viruses that encode at least one of the enzymes of this pathway with an overrepresentation (60%) of viruses potentially infecting pathogenic microbial hosts. Genetic studies with the Escherichia phage CAjan show that DpdA is essential to insert the 7-deazaguanine base in phage genomic DNA and that 2'-deoxy-7-deazaguanine modifications protect phage DNA from host restriction enzymes.
Medical subject headings
- Archaeal Viruses
- Bacteriophages
- DNA
- DNA Restriction Enzymes
- Guanine