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A Cell-to-cell Macromolecular Transport Assay in Planta Utilizing Biolistic Bombardment
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Published on: August 27, 2010

Tobamovirus replicase coding region is involved in cell-to-cell movement

K Hirashima1, Y Watanabe

  • 1Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan.

Journal of Virology
|August 17, 2001
PubMed

Insights

The replicase proteins of Tobacco mosaic virus (TMV) may play a role in cell-to-cell movement, a function previously attributed only to the movement protein (MP). This study investigated a chimeric virus with defects in movement, suggesting a broader role for TMV replicase.

Area of Science:

  • Plant Virology
  • Molecular Biology
  • Genetics

Background:

  • Tobacco mosaic virus (TMV) cell-to-cell movement is facilitated by its 30-kDa movement protein (MP).
  • The specific roles of TMV replicase proteins (126- and 183-kDa) in viral movement remain largely uncharacterized.

Purpose of the Study:

  • To investigate the potential involvement of TMV replicase proteins in viral cell-to-cell movement.
  • To analyze the movement defect of a chimeric TMV strain, UR-hel, with sequence differences in the replicase helicase-like domain.

Main Methods:

  • Construction and characterization of a chimeric TMV strain (UR-hel) derived from TMV-R and TMV-U1.
  • Comparative analysis of viral replication, genome synthesis, and movement protein (MP) accumulation between UR-hel and TMV-U1 in protoplasts.

Main Results:

  • The chimeric UR-hel virus exhibited a defect in cell-to-cell movement compared to the wild-type TMV-U1.
  • Replication, genome synthesis, and MP accumulation levels were comparable between UR-hel and TMV-U1 in inoculated protoplasts.
  • Amino acid sequence differences between UR-hel and TMV-U1 were localized to the helicase-like domain of the replicase.

Conclusions:

  • The observed movement defect in UR-hel, despite normal replication and MP levels, suggests a role for the replicase coding region in TMV cell-to-cell movement.
  • These findings challenge the exclusive role of MP in TMV cell-to-cell transport and implicate the replicase in this process.

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