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Publication Abstract from PubMed

Endogenous RNA transcription characterizes double-stranded RNA (dsRNA) viruses in the Reoviridae, a family that is exemplified by its simple, single-shelled member cytoplasmic polyhedrosis virus (CPV). Because of the lack of in situ structures of the intermediate stages of RNA-dependent RNA polymerase (RdRp) during transcription, it is poorly understood how RdRp detects environmental cues and internal transcriptional states to initiate and coordinate repeated cycles of transcript production inside the capsid. Here, we captured five high-resolution (2.8-3.5 A) RdRp-RNA in situ structures-representing quiescent, initiation, early elongation, elongation and abortive states-under seven experimental conditions of CPV. We observed the 'Y'-form initial RNA fork in the initiation state and the complete transcription bubble in the elongation state. These structures reveal that de novo RNA transcription involves three major conformational changes during state transitions. Our results support an ouroboros model for endogenous conservative transcription in dsRNA viruses.

Conservative transcription in three steps visualized in a double-stranded RNA virus.,Cui Y, Zhang Y, Zhou K, Sun J, Zhou ZH Nat Struct Mol Biol. 2019 Nov;26(11):1023-1034. doi: 10.1038/s41594-019-0320-0., Epub 2019 Nov 6. PMID:31695188^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.