title: Multiple regulatory mechanisms influence the activity of the transposon, Tam3, of Antirrhinum.
abstract: In Antirrhinum, several unique regulations of the transposon, Tam3, have been described. Tam3 activity in Antirrhinum is strictly controlled by the growing temperature of plants (low-temperature-dependent transposition: LTDT), by chromosomal position of Tam3 copy and by two specific repressor genes Stabiliser (St) and New Stabiliser (NSt). Here, the effects of the St and NSt loci on Tam3 transposition are compared. In cotyledons and hypocotyls, Tam3 is active even at high growing temperatures, indicating that LTDT does not operate when these organs are developing. This developmental regulation of Tam3 activity is differentially influenced by the St and NSt loci: St permits Tam3 transposition in cotyledons and hypocotyls, whereas NSt suppresses it in these organs. The effects of these host genes on Tam3 activity at the molecular level were examined. It was found that neither of these genes inhibits the transcription of the Tam3 transposase gene nor its translation, and that the Tam3 transposase has the potential to catalyze transposition in the St and NSt lines. The differences between the effects of St and NSt imply that they regulate Tam3 activity independently. Our molecular data indicate that their influence on Tam3 transposition seems to be nonepigenetic; possible mechanisms for their activity are discussed.
authors.affiliation: Laboratories of Plant Breeding and.
authors.forename: Takako
authors.initials: T
authors.lastname: Uchiyama
authors.affiliation: Laboratories of Plant Breeding and.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Saito
authors.affiliation: Laboratories of Plant Breeding and.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kuwabara
authors.affiliation: Laboratories of Crop Physiology, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
authors.forename: Kaien
authors.initials: K
authors.lastname: Fujino
authors.affiliation: Laboratories of Plant Breeding and.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kishima
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, Norfolk NR4 7UH, UK.
authors.forename: Cathie
authors.initials: C
authors.lastname: Martin
authors.affiliation: Laboratories of Plant Breeding and.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Sano
mesh_terms: D032161:Antirrhinum / Q000235:genetics* / Q000502:physiology*; D018548:Cotyledon / Q000502:physiology; D004251:DNA Transposable Elements / Q000502:physiology*; D044127:Epigenesis, Genetic; D035264:Flowers / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D017343:Genes, Plant / Q000502:physiology; D018546:Hypocotyl / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis
chemical_list: D004251:DNA Transposable Elements; D010940:Plant Proteins