Patterns of Isoform Variation for N Gene Subgenomic mRNAs in Betacoronavirus Transcriptomes

The nucleocapsid (N) protein is the most expressed protein in later stages of SARS-CoV-2 infection with several important functions. It is translated from a subgenomic mRNA (sgmRNA) formed by template switching during transcription. A recently described translation initiation site (TIS) with a CTG c...

Full description

Saved in:
Bibliographic Details
Main Authors: James J. Kelley, Andrey Grigoriev
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Viruses
Subjects:
Online Access:https://www.mdpi.com/1999-4915/17/1/36
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1832587386404470784
author James J. Kelley
Andrey Grigoriev
author_facet James J. Kelley
Andrey Grigoriev
author_sort James J. Kelley
collection DOAJ
description The nucleocapsid (N) protein is the most expressed protein in later stages of SARS-CoV-2 infection with several important functions. It is translated from a subgenomic mRNA (sgmRNA) formed by template switching during transcription. A recently described translation initiation site (TIS) with a CTG codon in the leader sequence (TIS-L) is out of frame with most structural and accessory genes including the N gene and may act as a translation suppressor. We analyzed multiple sequenced samples infected by SARS-CoV-2 and found that any single variant of this virus produces multiple isoforms of the N sgmRNA. The main isoform starting at TIS-L is out of frame, but two secondary dominant isoforms (present in nearly all samples) were found to restore the reading frame and likely involved in the regulation of N protein production. Analysis of sequenced samples infected by other coronaviruses revealed that such isoforms are also produced in their transcriptomes. In SARS-CoV, they restore the reading frame for a putative TIS (also a CTG codon) in the same relative position as in SARS-CoV-2. Positions of junction breakpoints relative to stem loop 3 in the 5′-UTR suggest similar mechanisms in SARS-CoV, SARS-CoV-2, and OC43, but not in MERS-CoV. These observations may be pertinent for antisense-based antiviral strategies.
format Article
id doaj-art-c3efe697ee5842c6bdf01927af3d5ad4
institution Kabale University
issn 1999-4915
language English
publishDate 2024-12-01
publisher MDPI AG
record_format Article
series Viruses
spelling doaj-art-c3efe697ee5842c6bdf01927af3d5ad42025-01-24T13:52:20ZengMDPI AGViruses1999-49152024-12-011713610.3390/v17010036Patterns of Isoform Variation for N Gene Subgenomic mRNAs in Betacoronavirus TranscriptomesJames J. Kelley0Andrey Grigoriev1Department of Biology, Center for Computational and Integrative Biology, Rutgers University, Camden, NJ 08102, USADepartment of Biology, Center for Computational and Integrative Biology, Rutgers University, Camden, NJ 08102, USAThe nucleocapsid (N) protein is the most expressed protein in later stages of SARS-CoV-2 infection with several important functions. It is translated from a subgenomic mRNA (sgmRNA) formed by template switching during transcription. A recently described translation initiation site (TIS) with a CTG codon in the leader sequence (TIS-L) is out of frame with most structural and accessory genes including the N gene and may act as a translation suppressor. We analyzed multiple sequenced samples infected by SARS-CoV-2 and found that any single variant of this virus produces multiple isoforms of the N sgmRNA. The main isoform starting at TIS-L is out of frame, but two secondary dominant isoforms (present in nearly all samples) were found to restore the reading frame and likely involved in the regulation of N protein production. Analysis of sequenced samples infected by other coronaviruses revealed that such isoforms are also produced in their transcriptomes. In SARS-CoV, they restore the reading frame for a putative TIS (also a CTG codon) in the same relative position as in SARS-CoV-2. Positions of junction breakpoints relative to stem loop 3 in the 5′-UTR suggest similar mechanisms in SARS-CoV, SARS-CoV-2, and OC43, but not in MERS-CoV. These observations may be pertinent for antisense-based antiviral strategies.https://www.mdpi.com/1999-4915/17/1/36coronavirusesSARS-CoV-2transcriptomeN genesubgenomic mRNA
spellingShingle James J. Kelley
Andrey Grigoriev
Patterns of Isoform Variation for N Gene Subgenomic mRNAs in Betacoronavirus Transcriptomes
Viruses
coronaviruses
SARS-CoV-2
transcriptome
N gene
subgenomic mRNA
title Patterns of Isoform Variation for N Gene Subgenomic mRNAs in Betacoronavirus Transcriptomes
title_full Patterns of Isoform Variation for N Gene Subgenomic mRNAs in Betacoronavirus Transcriptomes
title_fullStr Patterns of Isoform Variation for N Gene Subgenomic mRNAs in Betacoronavirus Transcriptomes
title_full_unstemmed Patterns of Isoform Variation for N Gene Subgenomic mRNAs in Betacoronavirus Transcriptomes
title_short Patterns of Isoform Variation for N Gene Subgenomic mRNAs in Betacoronavirus Transcriptomes
title_sort patterns of isoform variation for n gene subgenomic mrnas in betacoronavirus transcriptomes
topic coronaviruses
SARS-CoV-2
transcriptome
N gene
subgenomic mRNA
url https://www.mdpi.com/1999-4915/17/1/36
work_keys_str_mv AT jamesjkelley patternsofisoformvariationforngenesubgenomicmrnasinbetacoronavirustranscriptomes
AT andreygrigoriev patternsofisoformvariationforngenesubgenomicmrnasinbetacoronavirustranscriptomes