title: Identification of sequence elements regulating promoter activity and replication of a monopartite begomovirus-associated DNA beta satellite.
abstract: DNA beta is a circular single-stranded satellite DNA associated with certain monopartite begomoviruses (family Geminiviridae) which causes economically important diseases such as cotton leaf curl disease. DNA beta contains a single gene, betaC1, which encodes a pathogenicity protein responsible for symptom production. Transient expression studies in Nicotiana tabacum using the beta-glucuronidase reporter gene driven by a betaC1 promoter-deletion series of the DNA beta associated with cotton leaf curl Multan virus identified a 68 nt region (between -139 and -207) which is important for betaC1 transcription. This 68 nt region contains a G-box (CACGTG) located 143 nt upstream of the betaC1 start codon. Mutation of the G-box resulted in a significant reduction in betaC1 promoter activity and DNA beta replication efficiency. In addition, the G-box motif was found to bind specifically to a protein(s) in nuclear extracts prepared from tobacco leaf tissues. Our results indicate that interaction of the G-box motif with host nuclear factors is important for efficient gene expression and replication of DNA beta.
authors.affiliation: School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, SA 5064, Australia.
authors.forename: Omid
authors.initials: O
authors.lastname: Eini
authors.forename: S A Akbar
authors.initials: SA
authors.lastname: Behjatnia
authors.forename: Satish
authors.initials: S
authors.lastname: Dogra
authors.forename: Ian B
authors.initials: IB
authors.lastname: Dry
authors.forename: John W
authors.initials: JW
authors.lastname: Randles
authors.forename: M Ali
authors.initials: MA
authors.lastname: Rezaian
mesh_terms: D019677:Artificial Gene Fusion; D001483:Base Sequence; D053839:Begomovirus / Q000502:physiology*; D001665:Binding Sites; D004261:DNA Replication; D004276:DNA, Satellite / Q000096:biosynthesis* / Q000235:genetics*; D017791:Geminiviridae; D017930:Genes, Reporter; D005966:Glucuronidase / Q000096:biosynthesis / Q000235:genetics; D054884:Host-Pathogen Interactions; D008969:Molecular Sequence Data; D010935:Plant Diseases / Q000821:virology*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D017384:Sequence Deletion; D014026:Nicotiana / Q000821:virology; D014158:Transcription, Genetic
chemical_list: D004276:DNA, Satellite; D005966:Glucuronidase