Nucleic acid-binding properties of a bacterially expressed potato virus Y helper component-proteinase

Abstract

The potyvirus helper component-proteinase (HC-Pro) is a multifunctional protein previously reported to have affinity for polyribonucleotides. To investigate further the ability of HC-Pro to bind nucleic acids, the potato virus Y (PVY) LYE84 isolate HC-Pro gene was amplified, cloned in an Escherichia coli expression vector and sequenced. HC-Pro was expressed as a fusion with the maltose-binding protein and purified by affinity chromatography. Electrophoretic mobility-shift assays demonstrated that HC-Pro acts as a sequence nonspecific RNA-binding protein and suggest that more than one molecule of protein was bound per molecule of RNA. The HC-Pro RNA-binding activity was stable in 400 mu-NaC1 and temperature sensitive. The recombinant protein preferentially bound ssRNA over DNA or dsRNA and showed little, if any, affinity for poly(A). The possible implications of the RNA-binding activity of HC-Pro in potyvirus replication and movement are discussed.

Host-Specific Involvement of the HC Protein in the Long-Distance Movement of Potyviruses

“…HC-Pro is a multifunctional protein (41) with proteolytic activity (8), which is able to bind RNA in vitro (40) and to interact with itself (64). In addition to its function in aphid transmission (6), HC-Pro has been implicated in maintenance of genome amplification (36,38), cell-to-cell and long-distance movements (17,36,54,57), symptom expression (4,24,56), and enhancement of pathogenicity (47,59,67) and of longdistance movement (60) of other viruses in mixed infections.…”

The transfer of DNA from Agrobacterium tumefaciens into plants: a feast of fundamental insights

“…Integration may induce small ssDNA; nuclear shuttle, cell-to-cell movement (Pascal et al, 1994;Sanderfoot and Lazarowitz, (SqLCV) 1995;Sanderfoot et al, 1996) Cucumber mosaic virus (CMV) 3a ssRNA, ssDNA; cell-to-cell movement (Ding et al, 1995;Li and Palukaitis, 1996 HC-Pro ssRNA (Maia and Bernardi, 1996) *Additional movement proteins with SSB activity are described in Mushegian and Koonin (1993), Carrington et al (1996), and Lazarowitz and Beachy (1999). deletions, less than 100 bp, of plant DNA at the insertion site. In addition, integration also generates`®ller' DNA, less than 50 bp homologous to nearby plant DNA, at the T-DNA-plant junction.…”

Mutations in the HC-Pro gene of zucchini yellow mosaic potyvirus: effects on aphid transmission and binding to purified virions.

“…symptom severity (Atreya & Pirone, 1993), serving as a proteinase (Carrington et al, 1989), being involved in longdistance movement (Cronin et al, 1995 ;Rojas et al, 1997), and playing a role both in genome amplification (Kasschau et al, 1997) and in nucleic acid binding (Maia & Bernardi, 1996).…”