title: Cell-cycle, phase-specific activation of Maize streak virus promoters.
abstract: It is believed that geminiviral DNA replication is coupled to the cell-cycle regulatory complex of the plant cell and that the virus-early (complementary or C sense) gene products REP and REPA may be able to manipulate the regulation of the cycle. In this study, we examined expression from the promoters of Maize streak virus (MSV) in transgenic maize plants and cells to determine whether they showed cell-cycle specificity. Histochemical staining of plant roots containing "long and short" C-sense promoter sequences upstream of the GUS (beta-glucuronidase) reporter gene showed that promoter activity was restricted to the meristematic region of the roots and was enhanced by 2,4-dichlorophenoxy acetic acid (2,4-D) treatment. Analysis of reporter gene and cell-cycle-specific gene transcript levels coupled with flow cytometric data in synchronized transgenic maize cells revealed that all of the MSV promoters showed cell-cycle specificity. The coat protein gene promoter showed highest activity in early G2, whereas the C-sense promoter sequences produced two peaks of activity in the S and G2 cell-cycle phases.
authors.affiliation: Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged.
authors.forename: K
authors.initials: K
authors.lastname: Nikovics
authors.forename: J
authors.initials: J
authors.lastname: Simidjieva
authors.forename: A
authors.initials: A
authors.lastname: Peres
authors.forename: F
authors.initials: F
authors.lastname: Ayaydin
authors.forename: T
authors.initials: T
authors.lastname: Pasternak
authors.forename: J W
authors.initials: JW
authors.lastname: Davies
authors.forename: M I
authors.initials: MI
authors.lastname: Boulton
authors.forename: D
authors.initials: D
authors.lastname: Dudits
authors.forename: G V
authors.initials: GV
authors.lastname: Horváth
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D002874:Chromosome Mapping; D004261:DNA Replication; D017791:Geminiviridae / Q000235:genetics*; D015967:Gene Expression Regulation, Viral; D017930:Genes, Reporter; D016679:Genome, Viral; D005966:Glucuronidase / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics / Q000821:virology; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011523:Protoplasts / Q000166:cytology / Q000821:virology; D003313:Zea mays / Q000166:cytology* / Q000187:drug effects / Q000235:genetics / Q000821:virology*
chemical_list: D015084:2,4-Dichlorophenoxyacetic Acid; D005966:Glucuronidase