Alanine scanning of cucumber mosaic virus (CMV) 2b protein identifies different positions for cell-to-cell movement and gene silencing suppressor activity.
The multifunctional 2b protein of CMV has a role in the long distance and local movement of the virus, in symptom formation, in evasion of defense mediated by salicylic acid as well as in suppression of RNA silencing. The role of conserved amino acid sequence domains were analyzed previously in the protein function, but comprehensive analysis of this protein was not carried out until recently. We have analyzed all over the 2b protein by alanine scanning mutagenesis changing three consecutive amino acids (aa) to alanine. We have identified eight aa triplets as key determinants of the 2b protein function in virus infection. Four of them (KKQ/22-24/AAA, QNR/31-33/AAA, RER/34-36/AAA, SPS/40-42/AAA) overlap with previously determined regions indispensable in gene silencing suppressor function. We have identified two additional triplets necessary for the suppressor function of the 2b protein (LPF/55-57/AAA, NVE/10-12/AAA), and two other positions were required for cell-to-cell movement of the virus (MEL/1-3/AAA, RHV/70-72/AAA), which are not essential for suppressor activity.
Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary; Department of Plant Pathology, Corvinus University of Budapest, Budapest, Hungary.
Katalin
K
Nemes
Agricultural Institute, Centre for Agricultural Research, Hungarian Academy of Sciences Department of Applied Genomics, Martonvásár, Hungary.
Ákos
Á
Gellért
Agricultural Institute, Centre for Agricultural Research, Hungarian Academy of Sciences Department of Applied Genomics, Martonvásár, Hungary.
Ervin
E
Balázs
Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary; Agricultural Biotechnology Center, Gödöllő, Hungary.
Katalin
K
Salánki
D000409:Alanine; D017124:Conserved Sequence; D017799:Cucumovirus / Q000235:genetics* / Q000502:physiology*; D008958:Models, Molecular; D009068:Movement; D016296:Mutagenesis; D009154:Mutation; D009690:Nucleic Acid Conformation; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013045:Species Specificity; D014026:Nicotiana / Q000821:virology; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
C404227:2b protein, cucumber mosaic virus; D034741:RNA, Small Interfering; D014764:Viral Proteins; D000409:Alanine