Cauliflower mosaic virus gene VI product N-terminus contains regions involved in resistance-breakage, self-association and interactions with movement protein.
Cauliflower mosaic virus (CaMV) gene VI encodes a multifunctional protein (P6) involved in the translation of viral RNA, the formation of inclusion bodies, and the determination of host range. Arabidopsis thaliana ecotype Tsu-0 prevents the systemic spread of most CaMV isolates, including CM1841. However, CaMV isolate W260 overcomes this resistance. In this paper, the N-terminal 110 amino acids of P6 (termed D1) were identified as the resistance-breaking region. D1 also bound full-length P6. Furthermore, binding of W260 D1 to P6 induced higher beta-galactosidase activity and better leucine-independent growth in the yeast two-hybrid system than its CM1841 counterpart. Thus, W260 may evade Tsu-0 resistance by mediating P6 self-association in a manner different from that of CM1841. Because Tsu-0 resistance prevents virus movement, interaction of P6 with P1 (CaMV movement protein) was investigated. Both yeast two-hybrid analyses and maltose-binding protein pull-down experiments show that P6 interacts with P1. Although neither half of P1 interacts with P6, the N-terminus of P6 binds P1. Interestingly, D1 by itself does not interact with P1, indicating that different portions of the P6 N-terminus are involved in different activities. The P1-P6 interactions suggest a role for P6 in virus transport, possibly by regulating P1 tubule formation or the assembly of movement complexes.
Hapiak
Michael
M
Department of Biological Sciences, The University of Toledo, Toledo, OH 43606, United States.
Li
Yongzhong
Y
Agama
Keli
K
Swade
Shaddy
S
Okenka
Genevieve
G
Falk
Jessica
J
Khandekar
Sushant
S
Raikhy
Gaurav
G
Anderson
Alisha
A
Pollock
Justin
J
Zellner
Wendy
W
Schoelz
James
J
Leisner
Scott M
SM
D020816:Amino Acid Motifs; D017360:Arabidopsis / Q000821:virology*; D017796:Caulimovirus / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D054884:Host-Pathogen Interactions; D010935:Plant Diseases / Q000821:virology*; D011485:Protein Binding; D020798:Two-Hybrid System Techniques; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D014764:Viral Proteins