Carvalho, Claudine, M , Florentino, Lilian, H , Santos, Anésia, A , Rocha, Carolina, S , Zerbini, Francisco, M , Fontes, Elizabeth, P.B .
The network of interactions of the geminivirus nuclear shuttle protein.
The nuclear shuttle protein (NSP) from bipartite geminiviruses facilitates the intracellular transport of viral DNA from the nucleus to the cytoplasm and acts in concert with MP to promote the cell-to-cell spread of the viral DNA. The localization and function of NSP leads to the prediction that the viral protein may interact with host factors both in the nucleus and in the cytoplasm. In fact, NSP has been demonstrated to interact with two plasma membrane receptor-like kinase, designated AtNIK (NSP-interacting kinase) and AtNsAK (NSP-associated kinase), and also a nuclear acetyltransferase. In this study, we performed an extensive two-hybrid screening for CaLCuV NSP-interacting proteins, using a cDNA library from Arabidopsis and we isolated a nucleoporin-like protein, designated NAP (NSP-Associated Protein). The full-length protein, which is encoded by the At4g13350 gene, is similar to the human RIP that interacts with the REV nuclear shuttle protein from HIV. It possesses a zinc finger domain at the N-terminus and interacts with NSP through its C-terminal proline-rich domain. To assess directly the biological significance of NAP-NSP interaction, we identified a T-DNA insertion mutant in the NAP gene and selected for a homozygous Arabidopsis mutant line by PCR. The inactivation of the NAP gene was confirmed by RT-PCR. No accumulation of NAP transcripts was detected in the homozygous T-DNA insertion mutant, confirming it as a null allele. Wild type Col-0 plants and nap mutant lines were inoculated with CaLCuV DNA-A and DNA-B. Both Col-0 and nap-KO lines developed typical symptoms of CaLCuV infection at similar intensity and viral DNA accumulation was detected in all symptomatic plants. Inactivation of the NAP gene does not seem to affect CaLCuV infection in Arabidopsis. These results indicate either that the NAP-NSP interaction is not required for NSP function or the NAP homologues are functional analogs that are capable of replacing the NAP role in the null allele mutant.
Log in to add this item to your schedule
1 - Federal University of Viçosa, Dept. of Biochemistry and Molecular Biology, Bioagro, Viçosa, Minas Gerais, 36571-000, Brazil
2 - Federal University of Viçosa, Dept. of Biochemistry and Molecular Biology
3 - Federal University of Viçosa, Dept. of Plant Pathology
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM