The N-terminal region containing the zinc finger domain of tobacco streak virus coat protein is essential for the formation of virus-like particles
- 393 Downloads
Tobacco streak virus (TSV), a member of the genus Ilarvirus (family Bromoviridae), has a tripartite genome and forms quasi-isometric virions. All three viral capsids, encapsidating RNA 1, RNA 2 or RNA 3 and subgenomic RNA 4, are constituted of a single species of coat protein (CP). Formation of virus-like particles (VLPs) could be observed when the TSV CP gene was cloned and the recombinant CP (rCP) was expressed in E. coli. TSV VLPs were found to be stabilized by Zn2+ ions and could be disassembled in the presence of 500 mM CaCl2. Mutational analysis corroborated previous studies that showed that an N-terminal arginine-rich motif was crucial for RNA binding; however, the results presented here demonstrate that the presence of RNA is not a prerequisite for assembly of TSV VLPs. Instead, the N-terminal region containing the zinc finger domain preceding the arginine-rich motif is essential for assembly of these VLPs.
KeywordsCoat Protein Sucrose Density Gradient Brome Mosaic Virus Tobacco Streak Virus Cowpea Chlorotic Mottle Virus
We thank Dr. S. S. Indi, Dept. of Microbiology and Cell Biology, IISc, for his assistance in electron microscopy. We thank Department of Biotechnology and Department of Science and Technology (J.C. Bose fellowship to HSS), New Delhi, India, for the financial support. CM thanks CSIR, New Delhi, for Junior and Senior Research fellowships. We thank Prof. M.R.N. Murthy for critical reading of the manuscript.
- 18.Kurstak E (1981) Handbook of plant virus infections: comparative diagnosis. Elsevier/Noth Holland Biomedical Press, AmsterdamGoogle Scholar
- 32.Scott SW (2001) AAB Description of Plant Viruses. 381Google Scholar