scholarly journals The HCPro from thePotyviridaefamily: an enviable multitasking Helper Component that every virus would like to have

2017 ◽  
Vol 19 (3) ◽  
pp. 744-763 ◽  
Author(s):  
Adrián A. Valli ◽  
Araiz Gallo ◽  
Bernardo Rodamilans ◽  
Juan José López-Moya ◽  
Juan Antonio García
Keyword(s):  
Helper Component

Purification and characterization of potyvirus helper component

Virology ◽  
1985 ◽  
Vol 144 (1) ◽  
pp. 260-267 ◽  
Author(s):  
David W. Thornbury ◽  
Gary M. Hellmann ◽  
Robert E. Rhoads ◽  
Thomas P. Pirone
Keyword(s):  
Purification And Characterization ◽  
Helper Component

scholarly journals Tenuivirus utilizes its glycoprotein as a helper component to overcome insect midgut barriers for its circulative and propagative transmission

2019 ◽  
Vol 15 (3) ◽  
pp. e1007655 ◽  
Author(s):  
Gang Lu ◽  
Shuo Li ◽  
Changwei Zhou ◽  
Xin Qian ◽  
Qing Xiang ◽  
...  
Keyword(s):  
Insect Midgut ◽  
Helper Component

scholarly journals Biochemical Characterization of the Helper Component of Cauliflower Mosaic Virus

2001 ◽  
Vol 75 (18) ◽  
pp. 8538-8546 ◽  
Author(s):  
Eugenie Hebrard ◽  
Martin Drucker ◽  
Denis Leclerc ◽  
Thomas Hohn ◽  
Marilyne Uzest ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Biochemical Characterization ◽  
Active Form ◽  
Recombinant Baculovirus ◽  
Aphid Transmission ◽  
Cauliflower Mosaic Virus ◽  
Biologically Active ◽  
Size Exclusion ◽  
Viral Gene ◽  
Helper Component

ABSTRACT The helper component of Cauliflower mosaic virus is encoded by viral gene II. This protein (P2) is dispensable for virus replication but required for aphid transmission. The purification of P2 has never been reported, and hence its biochemical properties are largely unknown. We produced the P2 protein via a recombinant baculovirus with a His tag fused at the N terminus. The fusion protein was purified by affinity chromatography in a soluble and biologically active form. Matrix-assisted laser desorption time-of-flight mass spectrometry demonstrated that P2 is not posttranslationally modified. UV circular dichroism revealed the secondary structure of P2 to be 23% α-helical. Most α-helices are suggested to be located in the C-terminal domain. Using size exclusion chromatography and aphid transmission testing, we established that the active form of P2 assembles as a huge soluble oligomer containing 200 to 300 subunits. We further showed that P2 can also polymerize as long paracrystalline filaments. We mapped P2 domains involved in P2 self-interaction, presumably through coiled-coil structures, one of which is proposed to form a parallel trimer. These regions have previously been reported to also interact with viral P3, another protein involved in aphid transmission. Possible interference between the two types of interaction is discussed with regard to the biological activity of P2.

scholarly journals Loss of potyvirus transmissibility and helper-component activity correlate with non-retention of virions in aphid stylets

1996 ◽  
Vol 77 (5) ◽  
pp. 861-867 ◽  
Author(s):  
R. Y. Wang ◽  
E. D. Ammar ◽  
D. W. Thornbury ◽  
J. J. Lopez-Moya ◽  
T. P. Pirone
Keyword(s):  
Helper Component

scholarly journals In vitro association between the helper component–proteinase of zucchini yellow mosaic virus and cuticle proteins of Myzus persicae

2007 ◽  
Vol 88 (5) ◽  
pp. 1602-1610 ◽  
Author(s):  
Aviv Dombrovsky ◽  
Natan Gollop ◽  
Songbi Chen ◽  
Nor Chejanovsky ◽  
Benjamin Raccah
Keyword(s):  
Myzus Persicae ◽  
Zucchini Yellow Mosaic Virus ◽  
Yellow Mosaic Virus ◽  
Two Dimensional Gel Electrophoresis ◽  
Helper Component ◽  
Molecular Masses ◽  
Cuticle Proteins ◽  
Helper Component Proteinase ◽  
Persistently Transmitted Viruses

Potyviruses, as typical non-persistently transmitted viruses, are carried within the stylets of aphids. Cuticle proteins (CuPs), which are a major component of the insect cuticle, were examined for in vitro binding to the potyviral helper component–proteinase (HC–Pro). Proteins in 8 M urea extracts from Myzus persicae were separated by SDS-PAGE, electroblotted onto membranes and identified as CuPs by using specific antibodies to M. persicae CuP. Blotted M. persicae protein extracts were overlaid with two HC–Pros, differing by the presence of K or E in the KLSC domain. The HC–Pro with KLSC, known to assist transmission, was found to bind M. persicae proteins, whereas the HC–Pro with ELSC, being deficient in assisting transmission, did not. To identify CuPs that react with HC–Pro, protein extracts were separated by two-dimensional gel electrophoresis. Nine proteins reacting with HC–Pro were sequenced by mass spectrometry. Sequences of peptides in four proteins, of molecular masses between 22 and 31 kDa, were identified as CuPs according to comparison with sequences in GenBank. The putative CuPs from M. persicae that bind HC–Pro are potentially of interest in locating receptors for virions bound to HC–Pro in aphids’ stylets.

scholarly journals A Single Amino Acid Mutation in the Plum pox virus Helper Component-Proteinase Gene Abolishes Both Synergistic and RNA Silencing Suppression Activities

2005 ◽  
Vol 95 (8) ◽  
pp. 894-901 ◽  
Author(s):  
Pablo González-Jara ◽  
Felix A. Atencio ◽  
Belén Martínez-García ◽  
Daniel Barajas ◽  
Francisco Tenllado ◽  
...  
Keyword(s):  
Amino Acid ◽  
Point Mutation ◽  
Rna Silencing ◽  
Recombinant Virus ◽  
Single Amino Acid ◽  
Single Point Mutation ◽  
Plum Pox Virus ◽  
Helper Component ◽  
Silencing Suppression ◽  
Helper Component Proteinase

The effects on symptom expression of single amino acid mutations in the central region of the Plum pox virus (PPV) helper component-proteinase (HC-Pro) gene were analyzed in Nicotiana benthamiana using Potato virus X (PVX) recombinant viruses. PVX recombinant virus expressing the wild-type variant of PPV HC-Pro induced the expected enhancement of PVX pathogenicity, manifested as necrosis and plant death. Recombinant virus expressing a variant of PPV HC-Pro containing a single point mutation ( HCL134H) was unable to induce this synergistic phenotype. The RNA silencing suppressor activity of PPV HC-Pro was demonstrated in a transient silencing suppression assay. In contrast, the HCL134H mutant showed no such activity. These results indicate that a unique point mutation in PPV HC-Pro impaired its ability to suppress RNA silencing and abolished its capacity to induce synergism, and clearly shows for the first time the link between these two functions in potyvirus HC-Pro. Additionally, we compared the effects on virus accumulation in N. benthamiana plants infected with either the PVX recombinant constructs or with native viruses in double infection experiments. PVX (+) and (-) strand genomic RNA accumulated at similar levels in plants infected with PVX recombinants, leading to an increase in PVX pathology, compared with plants infected with PVX alone. This finding confirms that the enhancement of pathogenicity associated with synergistic interaction is not a consequence of more efficient PVX replication due to RNA silencing suppression by PPV HC-Pro.

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