IMR Press / FBL / Volume 23 / Issue 1 / DOI: 10.2741/4579

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on as a courtesy and upon agreement with Frontiers in Bioscience.


Leader sequences of coronavirus are altered during infection

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1 Department of Microbiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
2 Beijing Institute of Biotechnology, No. 20 Dongdajie Street, Fengtai District, Beijing 100071, China
Front. Biosci. (Landmark Ed) 2018, 23(1), 27–35;
Published: 1 January 2018
(This article belongs to the Special Issue Leader sequences of coronavirus are altered during infection)

The life cycle of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) involves a unique process called discontinuous transcription by which a set of 3’ coterminal subgenomic mRNAs (sgmRNA) with identical 5’ leader sequences can be generated. The current study demonstrates that the replication intermediates of minus strand of subgenomic RNA (sgRNA) can be readily recovered from SARS-CoV infected cells. A novel sgmRNA (M-1) was identified as a short version of membrane (M) gene. Transcriptional regulatory sequences (TRS) of SARS-CoV and Mouse Hepatitis Virus (MHV) sgmRNAs contain a species specific core element (CE). The sizes of leader sequences in MHVs vary not only in different viral strains but also among different genes in the same strain. Leader alterations such as deletion and nucleotide substitution were observed in MHVs, while a dynamic one-orientation "sequential deletion" was found among the leaders of 76 SARS-CoV isolates. These results imply that the leader sequence of coronavirus might be unstable and leader alterations during SARS-CoV transmission in humans might have negative impact on its viral infectivity.

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