Distinct regions at the N-terminus of the Cucumber necrosis virus coat protein target chloroplasts and mitochondria.
Cucumber necrosis virus (CNV) is a spherical virus consisting of 180 identical coat protein (CP) subunits. The N-terminus of the CP subunit contains a 58aa RNA binding (R) domain and a 34aa arm that connects the R domain to the shell. These regions are known to play critical roles in virus assembly and disassembly. It has recently been shown that a region encompassing the arm can function as a chloroplast transit peptide (TP) in infected plants and that targeting may represent a means for virus particle disassembly. In this study, we further delineate the TP region and show that a 22aa sequence at the N-terminus of the shell enhances chloroplast targeting. We also demonstrate that R domain specifically co-localizes with mitochondria in agroinfiltrated plants. Deletion analyses show that the N-terminal 39 amino acids of the R domain are sufficient for mitochondrial targeting and that this region contains features typical of mitochondrial presequences. The R/arm region is found to be dually targeted to mitochondria and chloroplasts suggesting that this region of the CP plays a critical role in determining the fate of CP during the infection process.
Hui
Elizabeth
E
Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada.
Xiang
Yu
Y
Rochon
D'Ann
D
D036022:Capsid Proteins / Q000378:metabolism*; D002736:Chloroplasts / Q000737:chemistry / Q000378:metabolism*; D008928:Mitochondria / Q000737:chemistry / Q000378:metabolism*; D021381:Protein Transport; D017384:Sequence Deletion; D014026:Nicotiana / Q000821:virology; D017864:Tombusvirus / Q000472:pathogenicity*; D037521:Virulence Factors / Q000378:metabolism*
D036022:Capsid Proteins; D037521:Virulence Factors