Open AccessConservative transcription in three steps visualized in a double-stranded RNA virus
Author(s) -
Yanxiang Cui,
Y. Zhang,
Kebin Zhou,
Jingchen Sun,
Ziwei Zhou
Publication year - 2019
Publication title -
nature structural and molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.448
H-Index - 270
eISSN - 1545-9993
pISSN - 1545-9985
DOI - 10.1038/s41594-019-0320-0
Subject(s) - rna silencing , transcription (linguistics) , biology , rna , rna polymerase , rna dependent rna polymerase , rna polymerase ii , capsid , microbiology and biotechnology , genetics , virus , gene , gene expression , rna interference , promoter , linguistics , philosophy
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 Å) 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.