|
Mode of Action (MoA)
|
degrades msDNA and ncRNA of the retron.
|
|
Evidence
|
Rad (ORF75 of SP15, named retron anti-defense or Rad) was pinpointed within an 8 kb Anti-Defense Island (ADI) whose deletion impaired phage infectivity against E. coli strains carrying retrons Ec67, Ec78, and Ec83. Cloning of this ORF restored infectivity, confirming Rad’s anti-retron function. Expression (ECO_0000017) of Rad in E. coli carrying retrons Ec67, Ec78, or Ec83 restored infectivity of otherwise sensitive phages (T5n or ΦSP15m). Single-point mutations in conserved residues (R13E, P33T, I88T, D135H, E156H) led to partial loss of Rad activity (ECO_0001113). Double mutations completely abolished anti-retron function (ECO_0001113). Co-expression of Rad with retron systems led to a marked decrease in the production of msDNA and its precursor ncRNA (msr-msd), but not RT or effector protein transcripts. This implies Rad degrades the ncRNA necessary for msDNA synthesis, directly interfering with retron function. Results on Rad are not included in the peer-review version of the paper.
|
|
MoA Category
|
degrades or sequesters molecules utilised by host defence systems
|
|
Subtype(s) of the defence system(s) inhibited by the protein
Defence Subtype
|
Escherichia coli type 1A retron (Ec83)
|
|
Relevant publication(s)
DOI
|
10.1101/2023.03.15.532788,
10.1038/s41467-024-53789-y
|
|
Other components of the anti-defence system
Multicomponent System
|
-
|
|
Known structure in PDB
PDB ID
|
-
|
|
Genome(s) encoding the protein
Protein Source
|
Escherichia coli phage ΦSP15
|
|
Defence system(s) inhibited by the protein
Defences
|
Retron
|