Research Interests

This laboratory studies the molecular biology of plant RNA viruses, focussing on turnip yellow mosaic virus (TYMV) a small virus with a simple genome consisting of one strand of RNA. A long-standing interest is the understanding of the role of the transfer RNA mimicry of the 3´-end of the viral genome, an interest that has led to studies on the RNA binding properties of the translation elongation factor EF-1a (eEF1A).
We have recently extended our studies on RNA replication to identifying the features that direct transcription by Qß-replicase. View full version

 
Areas of Research: VIROLOGY; RNA-PROTEIN INTERACTION: RNA replication in positive strand RNA viruses; molecular biology of turnip yellow mosaic virus; properties of EF-1a and other tRNA-interacting proteins; factors controlling initiation of transcription by Qß-replicase
 

Focus: Understanding the mechanism of RNA replication in positive strand RNA viruses, and the RNA recognition properties of EF-1a.
 

Experimental Approaches: A wide range of molecular biological and biochemical techniques including DNA mutagenesis, transcription-coupled PCR, RNA synthesis assays by viral polymerases, in vitro transcription of RNA, aminoacylation of tRNA, EF-1a binding assays. We also monitor viral function in vivo, using whole plant infection and protoplast inoculation experiments, followed by analysis of RNA and protein products with Northern and Western blot assays.
 

Highlights: We have discovered (1) a new structure-based specificity mechanism that permits a viral RNA (turnip yellow mosaic virus = TYMV) to be specifically copied in the absence of a conventional unique promoter sequence; (2) the tRNA-like structure that is part of the TYMV genome probably functions as a novel negative regulator of genome replication; (3) EF-1a can bind aminoacylated viral tRNA-like structures with the same high affinity as aminoacylated tRNA.
 

Importance of Research: Our studies on the replication of TYMV RNA are relevant to many if not all positive strand RNA viruses. TYMV is not a crop pathogen, but cucumber mosaic and tobacco mosaic viruses are among related viruses that do cause crop losses. The replication strategies of polio, rubella and yellow fever viruses also share commonalities with that of TYMV. Understanding replication will lead to new antiviral treatments. EF-1a is an abundant protein that has been little investigated but shows promise of interesting roles other than its canonical role in translation that are currently little explored. It plays a key role in protein synthesis and may act to interface the protein synthesis machinery to the changing demands within the cell.