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Structural basis of antiphage defence by an ATPase-associated reverse transcriptase

ABSTRACT: Reverse transcriptases (RTs) have well-established roles in the replication and spread of retroviruses and retrotransposons. However, recent evidence suggests that RTs have been conscripted by cells for diverse roles in antiviral defence. Here we determine structures of a type I-A retron, which explain how RNA, DNA, RT, HNH-nuclease and four molecules of an SMC-family ATPase assemble into a 364 kDa complex that provides phage defence. We show that phage-encoded nucleases trigger degradation of the retron-associated DNA, leading to disassembly of the retron and activation of the HNH nuclease. The HNH nuclease cleaves tRNASer, stalling protein synthesis and arresting viral replication. Taken together, these data reveal diverse and paradoxical roles for RTs in the perpetuation and elimination of genetic parasites.

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ORGANISM(S): Escherichia Coli

SUBMITTER: Jerrin Thomas George

LAB HEAD: Blake Wiedenheft

PROVIDER: PXD061597 | Pride | 2025-05-23

REPOSITORIES: pride

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			Action	DRS
	WiedenheftB_071824_02.raw__F022380_.mzid	Mzid
	WiedenheftB_071824_02.raw__F022380_.mzid_WiedenheftB_071824_02.raw__F022380_.MGF	Mzid
	WiedenheftB_071824_05.raw__F022383_.mzid	Mzid
	WiedenheftB_071824_05.raw__F022383_.mzid_WiedenheftB_071824_05.raw__F022383_.MGF	Mzid
	WiedenheftB_071824_06.raw__F022384_.mzid	Mzid

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