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Sendai virus C proteins are categorically nonessential gene products but silencing their expression severely impairs

A Kurotani1, K Kiyotani, A Kato

  • 1Department of Viral Infection, Institute of Medical Science, University of Tokyo, Japan.

Genes to Cells : Devoted to Molecular & Cellular Mechanisms
|May 30, 1998
PubMed
Abstract

Insights

Sendai virus C proteins are not essential but greatly aid viral replication in cells and are vital for growth and disease in mice. This research offers the first full functional analysis of these accessory proteins in Mononegavirales.

Area of Science:

  • Virology
  • Molecular Biology
  • RNA Viruses

Background:

  • Sendai virus (SeV), a Paramyxoviridae member, encodes accessory C proteins (C', C, Y1, Y2) from the P/C mRNA.
  • The C protein is the most abundant species, but the functions of all C proteins remain largely unknown.
  • The essentiality and roles of C-like proteins in Mononegavirales viruses are not well-defined.

Purpose of the Study:

  • To investigate the function and essentiality of Sendai virus (SeV) accessory C proteins.
  • To determine the role of C proteins in viral replication, gene expression, and pathogenesis.

Main Methods:

  • Utilized a reverse genetics system to create SeV mutants with silenced C protein genes.
  • Generated viruses lacking specific C proteins (C/C'(-) and 4C(-)) to assess their impact on viral replication.
  • Infected various cell types, embryonated eggs, and mice to evaluate viral growth and pathogenicity.

Main Results:

  • Mutants lacking C and C' (C/C'(-)) showed severely attenuated replication in vitro and were nonpathogenic in mice.
  • Gene expression and genome replication were impaired in C/C'(-) viruses.
  • A viable mutant lacking all four C proteins (4C(-)) was generated, indicating partial redundancy but critical roles for C proteins.

Conclusions:

  • SeV C proteins are nonessential for viral viability but significantly enhance replication in vitro.
  • These accessory proteins are indispensable for efficient viral multiplication and pathogenesis in vivo.
  • This study provides the first comprehensive functional analysis of accessory C proteins within the Mononegavirales order.

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