Research Groups

Plant Biology: Plant Molecular Biology

Research Interests and Description

Staff Research Scientist: Nirupam Roy Choudhury

Research Interests

Study of the replication machinery of geminiviruses.

Description of Research

Geminiviruses are plant pathogens and replicate in the nucleus of the host plant in a cell cycle dependent manner. Our research group is interested in elucidating the mechanism of geminiviral DNA replication taking Mungbean yellow mosaic India virus (MYMIV) and Tomato leaf curl virus (ToLCV) as the model systems. We have observed that geminiviral Rep protein possesses intrinsic DNA binding, nicking, ATPase and helicase activities etc., which are required for its involvement in the replication process. Currently we are interested in identification and characterization of various host factors which participate during geminiviral replication. By employing techniques like Phage display and Yeast two hybrid, we have been able to identify few such host factors and such studies are in continuation.

Recently, we have also been able to constitute an in vitro replication assay system using nuclear extract from Saccharomyces cerevisiae (yeast) and our preliminary studies show that such extract is very efficient in supporting the replication of vectors constructed based on geminiviral genome. We are currently extrapolating the work with the nuclear extracts prepared from various yeast mutants and directly checking the geminiviral DNA replication efficiency in such extracts.

Recent Publications

Singh D.K., Islam M.N., Roy Choudhury N., Karjee S., Mukherjee S.K. 2007. The 32 kDa subunit of replication protein A (RPA) participates in the DNA replication of Mung bean yellow mosaic India virus (MYMIV) by interacting with the viral Rep protein. Nucleic Acids Res. 35, 755-770

Nitharwal R.G., Paul S., Dar A., Roy Choudhury N., Soni R. K., Prusthy D., Sinha S., Kashav T., Mukhopadhyay G., Chaudhury T., Gourinath S., Dhar S.K. 2007. The domain structure of helicobacter pylori DnaB helicase: The N-terminal domain can be dispensable for helicase activity whereas the extreme C-terminal region is essential for its function. Nucleic Acids Res. 35, 2861-2874

Roy Choudhury N., Malik P.S., Singh D.K., Islam M.N., Kaliappan K., Mukherjee S.K. 2006. The oligomeric Rep protein of Mungbean yellow mosaic India virus (MYMIV) is a likely replicative helicase. Nucleic Acids Res. 34, 6362-6377

Raghavan, V., Malik, P.S., Roy Choudhury, N., Mukherjee, S.K. 2004. DNA-A Component of a Plant Geminivirus (Indian mungbean yellow mosaic virus) Replicates in Budding Yeast Cells. J. Virol. 78, 2405-2413

Bagewadi, B., Chen, S., Lal S.K., Roy Choudhury N., Mukherjee S.K. 2004. PCNA Interacts with Indian mungbean yellow mosaic virus Rep and Downregulates Rep Activity. J. Virol 78, 11890-11903

Soni, R., Mehra, P., Roy Choudhury N., Mukhopadhay G., Dhar S. 2003. Functional characterisation of Helicobacter pylori DnaB helicase. Nucleic Acids Res. 31, 6828-6840