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.
Department of Biological Sciences, The University of Toledo, Toledo, OH 43606, United States.
Michael
M
Hapiak
Yongzhong
Y
Li
Keli
K
Agama
Shaddy
S
Swade
Genevieve
G
Okenka
Jessica
J
Falk
Sushant
S
Khandekar
Gaurav
G
Raikhy
Alisha
A
Anderson
Justin
J
Pollock
Wendy
W
Zellner
James
J
Schoelz
Scott M
SM
Leisner
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