title: Replication modes of Maize streak virus mutants lacking RepA or the RepA-pRBR interaction motif.
abstract: The plant-infecting mastreviruses (family Geminiviridae) express two distinct replication-initiator proteins, Rep and RepA. Although RepA is essential for systemic infectivity, little is known about its precise function. We therefore investigated its role in replication using 2D-gel electrophoresis to discriminate the replicative forms of Maize streak virus (MSV) mutants that either fail to express RepA (RepA(-)), or express RepA that is unable to bind the plant retinoblastoma related protein, pRBR. Whereas amounts of viral DNA were reduced in two pRBR-binding deficient RepA mutants, their repertoires of replicative forms changed only slightly. While a complete lack of RepA expression was also associated with reduced viral DNA titres, the only traces of replicative intermediates of RepA(-) viruses were those indicative of recombination-dependent replication. We conclude that in MSV, RepA, but not RepA-pRBR binding, is necessary for single-stranded DNA production and efficient rolling circle replication.
authors.affiliation: Department of Molecular Biology and Plant Virology, Institute of Biology, University of Stuttgart, Pfaffenwaldring 57, Stuttgart, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Ruschhaupt
authors.forename: Darren P
authors.initials: DP
authors.lastname: Martin
authors.forename: Francisco
authors.initials: F
authors.lastname: Lakay
authors.forename: Marion
authors.initials: M
authors.lastname: Bezuidenhout
authors.forename: Edward P
authors.initials: EP
authors.lastname: Rybicki
authors.forename: Holger
authors.initials: H
authors.lastname: Jeske
authors.forename: Dionne N
authors.initials: DN
authors.lastname: Shepherd
mesh_terms: D002478:Cells, Cultured; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D026762:Maize streak virus / Q000235:genetics / Q000502:physiology*; D017384:Sequence Deletion; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D019562:Viral Load; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication; D003313:Zea mays / Q000821:virology
chemical_list: D015534:Trans-Activators; D014764:Viral Proteins; C045264:replication initiator protein; D004265:DNA Helicases