Viruses encode tRNA and anti-retron to evade bacterial immunity [PrrC170]
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1078003 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR28009961.fastq.gz | Fastqsanger.gz | |||
| SRR28009962.fastq.gz | Fastqsanger.gz | |||
| SRR28009963.fastq.gz | Fastqsanger.gz | |||
| SRR28009964.fastq.gz | Fastqsanger.gz |
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Similar Datasets
Project description:Viruses encode tRNA and anti-retron to evade bacterial immunity
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Project description:Viruses encode tRNA and anti-retron to evade bacterial immunity [Ec83]
| PRJNA1078004 | ENA
Project description:Retrons are bacterial genetic retroelements that encode reverse transcriptase capable of producing multicopy single-stranded DNA (msDNA) and function as antiphage defense systems. Phages employ several strategies to counter the host defense systems, but no mechanisms for evading retrons are known. Here, we show that tRNATyr and Rad (retron anti defense) of T5 phage family inhibit the defense activity of retron 78 and a broad range of retrons, respectively. The effector protein of retron 78, ptuAB, specifically degraded tRNATyr leading abortive infection, but phage countervailed this defense by supplying tRNATyr. Rad inhibited retron function by degrading noncoding RNA, the precursor of msDNA. In summary, we demonstrated that viruses encode at least two independent strategies for overcoming bacterial defense systems: anti-defense, such as Rad, and defense canceler, like tRNA.
2025-06-01 | GSE259275 | GEO
Project description:Retrons are bacterial genetic retroelements that encode reverse transcriptase capable of producing multicopy single-stranded DNA (msDNA) and function as antiphage defense systems. Phages employ several strategies to counter the host defense systems, but no mechanisms for evading retrons are known. Here, we show that tRNATyr and Rad (retron anti defense) of T5 phage family inhibit the defense activity of retron 78 and a broad range of retrons, respectively. The effector protein of retron 78, ptuAB, specifically degraded tRNATyr leading abortive infection, but phage countervailed this defense by supplying tRNATyr. Rad inhibited retron function by degrading noncoding RNA, the precursor of msDNA. In summary, we demonstrated that viruses encode at least two independent strategies for overcoming bacterial defense systems: anti-defense, such as Rad, and defense canceler, like tRNA.
2024-10-10 | GSE256078 | GEO
Project description:Retrons are bacterial genetic retroelements that encode reverse transcriptase capable of producing multicopy single-stranded DNA (msDNA) and function as antiphage defense systems. Phages employ several strategies to counter the host defense systems, but no mechanisms for evading retrons are known. Here, we show that tRNATyr and Rad (retron anti defense) of T5 phage family inhibit the defense activity of retron 78 and a broad range of retrons, respectively. The effector protein of retron 78, ptuAB, specifically degraded tRNATyr leading abortive infection, but phage countervailed this defense by supplying tRNATyr. Rad inhibited retron function by degrading noncoding RNA, the precursor of msDNA. In summary, we demonstrated that viruses encode at least two independent strategies for overcoming bacterial defense systems: anti-defense, such as Rad, and defense canceler, like tRNA.
2024-10-10 | GSE256077 | GEO
Project description:Retrons are bacterial genetic elements that encode a reverse transcriptase and, in combination with toxic effector proteins, can serve as antiphage defense systems. However, the mechanisms of action of most retron effectors, and how phages evade retrons, are not well understood. Here, we show that some phages can evade retrons and other defense systems by producing specific tRNAs. We find that expression of retron-Eco7 effector proteins (PtuA and PtuB) leads to degradation of tRNA-Tyr and abortive infection. The genomes of T5 phages that evade retron-Eco7 include a tRNA-rich region, including a highly expressed tRNA-Tyr gene, which confers protection against retron-Eco7. Furthermore, we show that other phages (T1, T7) can use a similar strategy, expressing a tRNA-Lys, to counteract a tRNA anticodon defense system (PrrC170).
2024-09-12 | GSE229290 | GEO
Project description:Retrons are prokaryotic genetic elements involved in anti-phage defense and consist of a non-coding RNA, a reverse transcriptase (RT), and various effector proteins. Retron-Eco7 (previously known as Retron-Ec78) from Escherichia coli encodes two effector proteins (a PtuA ATPase and a PtuB nuclease) and degrades host tRNATyr upon phage infection, thereby protecting host cells against invading phages. However, its defense mechanism remains elusive. Here, we report the cryo-electron microscopy structures of the Retron-Eco7 complex, comprising the RT, multicopy single-stranded DNA (msDNA), PtuA, and PtuB. The Retron-Eco7 structure reveals that the RT–msDNA complex associates with two PtuA–PtuB complexes, potentially inhibiting their nuclease activity and suppressing bacterial growth arrest prior to phage infection. Furthermore, we found that a phage-encoded D15 nuclease acts as a trigger for the Retron-Eco7 system, cleaving the msDNA bound to the complex and facilitating the dissociation of PtuA–PtuB from RT–msDNA. Our data indicate that msDNA cleavage by D15 is the initial step required for the specific cleavage of host tRNATyr by the PtuA–PtuB nuclease, which leads to abortive infection. Overall, this study provides mechanistic insights into the Retron-Eco7 system and highlights the diversity of prokaryotic anti-phage defense mechanisms.
2025-10-23 | GSE293394 | GEO
Project description:Retrons are toxin-antitoxin systems protecting bacteria against bacteriophages via abortive infection. The Retron-Eco1 antitoxin is formed by a reverse transcriptase (RT) and a non-coding RNA (ncRNA)/multi-copy single-stranded DNA (msDNA) hybrid that neutralizes an uncharacterized toxic effector. Yet, the molecular mechanisms underlying phage defense remain unknown. Here, we show that the N-glycosidase effector, which belongs to the STIR superfamily, hydrolyzes NAD+ during infection. Cryoelectron microscopy (cryo-EM) analysis shows that the msDNA stabilizes a filament that cages the effector in a low-activity state in which ADPr, a NAD+ hydrolysis product, is covalently linked to the catalytic E106 residue. Mutations shortening the msDNA induce filament disassembly and the effector’s toxicity, underscoring the msDNA role in immunity. Furthermore, we discovered a phage-encoded Retron-Eco1 inhibitor (U56) that binds ADPr, highlighting the intricate interplay between retron systems and phage evolution. Our work outlines the structural basis of Retron-Eco1 defense, uncovering ADPr’s pivotal role in immunity.
2024-05-23 | PXD044835 | Pride
Project description:Small RNAs play essential regulatory roles in genome stability, development and stress responses in most eukaryotes. Plants encode DICER-LIKE (DCL) RNaseIII enzymes, including DCL1, which produces miRNAs, and DCL2, DCL3 and DCL4, which produce diverse size classes of siRNA. Plants also encode RNASE THREE-LIKE (RTL) enzymes that lack DCL-specific domains and whose function is largely unknown. Small RNA sequencing in plants over-expressing RTL1 or RTL2 or lacking RTL2 revealed that RTL1 over-expression inhibits the accumulation of all types of small RNAs produced by DCL2, DCL3 and DCL4, indicating that RTL1 is a general suppressor of plant siRNA pathways. By contrast, RTL2 plays minor, if any, role in the small RNA repertoire. In vivo and in vitro assays revealed that RTL1 prevents siRNA production by degrading dsRNA before they are processed by DCL2, DCL3 and DCL4. The substrate of RTL1 cleavage is likely long perfect (or near-perfect) dsRNA, consistent with the RTL1-insensitivity of miRNAs, which derive from short imperfect dsRNA. RTL1 is naturally expressed only weakly in roots, but virus infection strongly induces its expression in leaves, suggesting that RTL1 induction is a general strategy used by viruses to counteract the siRNA-based plant antiviral defense. Accordingly, transgenic plants over-expressing RTL1 are more sensitive to TYMV infection than wild-type plants, likely because RTL1 prevents the production of antiviral siRNAs. However, TCV, TVCV and CMV, which encode stronger suppressors of RNA silencing (VSR) than TYMV, are insensitive to RTL1 over-expression. Indeed, TCV VSR inhibits RTL1 activity, suggesting that inducing RTL1 expression and dampening RTL1 activity is a dual strategy used by viruses to establish a successful infection. These results reveal another level of complexity in the evolutionary battle between viruses and plant defenses. Flower sRNA profiles in diverse conditions involving RTL1 and RTL2
2013-09-10 | E-GEOD-49866 | biostudies-arrayexpress
Project description:Viruses compete with other viruses for limited cellular recourses, and some viruses deliver defense mechanisms that protect the host from competing genetic parasites. PARIS is a defense system, often encoded in viral genomes, that is composed of a 53 kDa ABC ATPase (AriA) and a 35 kDa TOPRIM nuclease (AriB). Here we show that AriA and AriB assemble into a 425 kDa supramolecular immune complex. We use cryo-EM to determine the structure of this complex which explains how six molecules of AriA assemble into a propeller-shaped scaffold that coordinates three subunits of AriB. ATP-dependent detection of foreign proteins triggers the release of AriB, which assembles into a homodimeric nuclease that blocks infection by cleaving the host Lysine tRNA. Phage T5 can subvert PARIS immunity through expression of a non-cleavable tRNA variant. Collectively, these data explain how AriA functions as an ATP-dependent sensor that detects viral proteins and activates the AriB toxin. PARIS is one of an emerging set of immune systems that form macromolecular complexes for the recognition of foreign proteins, rather than foreign nucleic acids.
2024-06-24 | GSE270519 | GEO