{
  "id": 9603362,
  "title": "Dual ATPase-activated DNA hemimethylation and cleavage by the MANTIS defence system",
  "url": "https://urgent.news/2026/09/24/dual-atpase-activated-dna-hemimethylation-and-cleavage-by-the-mantis",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-24T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.23.753747v1?rss=1"
  },
  "original_language": "en",
  "account": "Bacterial defence systems act as crucial barriers against horizontal gene transfer and phage infection. While restriction-modification systems were initially discovered and remain common, the self/non-self discrimination in many methylation-based systems remains unclear. The MANTIS (Methyltransferase, ATPases and Nuclease Targeting Inverted-repeat Sequences) defence system, previously known as Gao_RL, has now been elucidated.\n\nUtilizing phage infection and plasmid transformation assays in Pseudomonas aeruginosa, biochemical reconstitution, and structural biology analyses, researchers have discovered that MANTIS establishes self-identity through adenine hemimethylation of specific DNA sequences. The system's activation requires the co-regulators MtsA and MtsB, both of which are necessary for recruiting and activating the methyltransferase MtsC. This discovery reveals an ATP-dependent mechanism for epigenetic modification.\n\nUpon DNA recognition by the MtsABC complex, a dimeric helicase-nuclease effector (MtsD) is triggered to restrict the target site. The restriction activity's efficiency depends on the architecture of the target site: inverted pairs of unmodified sites support robust restriction, while direct repeats or single sites are restricted less efficiently. Virulent phages exhibit strand-biased depletion of MANTIS target sites, indicating an evolutionary pressure to evade restriction.\n\nThe findings shed light on how dual ATPases couple self-modification to non-self restriction, providing a framework to understand the growing landscape of methylation-based defence systems.",
  "summary": "Bacterial defence systems are diverse and form major barriers to horizontal gene transfer and bacteriophage (phage) infection. Though restriction-modification systems were the first such defences discovered and remain the most widespread, the basis of self/non-self discrimination in many newly identified methylation-based systems remains unclear. Here, we define the mechanism of a widely…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}