title: Analysis of putative interactions between potyviral replication proteins and plant retinoblastoma proteins.
abstract: Sequence comparisons suggest that the RNA-dependent RNA polymerase (NIb) of potyviruses and bymoviruses, as well as the viral polymerase of potexviruses may contain a putative retinoblastoma protein (pRb) binding motif. The possibility that the potyviral NIb may function in the nucleus through interactions with plant pRb-related (RBR) proteins, and the modifications of the cell cycle was investigated by a combination of mutagenesis of the NIb and yeast two-hybrid system (YTHS). Mutation of a highly conserved glutamic acid residue in the putative pRb-binding motif of the NIb had no detectable phenotypic effect on replication of Potato virus A (PVA). Furthermore, the NIb proteins from Potato virus V and PVA failed to interact with maize or tobacco RBR proteins in yeast. Although the conservation of the motif for pRb interaction in plant RNA viruses is intriguing, these proteins from plant RNA viruses appear not to interact with plant RBR proteins.
authors.affiliation: Department of Plant Biology, Genetics Centre, SLU, Uppsala, Sweden.
authors.forename: Igor
authors.initials: I
authors.lastname: Oruetxebarria
authors.forename: Anders
authors.initials: A
authors.lastname: Kvarnheden
authors.forename: Jari P T
authors.initials: JP
authors.lastname: Valkonen
mesh_terms: D012321:DNA-Directed RNA Polymerases; D010450:Endopeptidases; D016679:Genome, Viral; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000378:metabolism*; D017800:Potyvirus / Q000737:chemistry*; D016160:Retinoblastoma Protein / Q000378:metabolism*; D014026:Nicotiana / Q000821:virology*; D020798:Two-Hybrid System Techniques; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D016160:Retinoblastoma Protein; D014764:Viral Proteins; C061396:nuclear inclusion protein b, mosaic viruses; D012321:DNA-Directed RNA Polymerases; D010450:Endopeptidases; C059992:nuclear inclusion protein a, mosaic viruses