title: Sucrose Represses the Developmentally Controlled Transient Activation of the Plastocyanin Gene in Arabidopsis thaliana Seedlings.
abstract: The plastocyanin (PC) gene of Arabidopsis thaliana is activated independently of light during early seedling development. In etiolated seedlings, PC mRNA levels increase transiently and a maximum dark level is reached after 2 d of growth in darkness. In etiolated transgenic seedlings carrying a chimeric PC-promoter: luciferase fusion gene, luciferase activity is similarly increased after 2 d of growth. The transient increase in PC mRNA and luciferase activity levels can be repressed by sucrose. Nonmetabolizable sugars and polyethylene glycol do not have a major effect on PC gene expression. Also, light-grown seedlings show a similar transient and sucrose-sensitive increase in PC mRNA levels and luciferase activity, as in dark-grown seedlings, but here expression levels are 15- fold higher. These findings suggest the presence of a sucrose-sensitive, developmentally controlled expression mechanism that operates independently of light.
authors.affiliation: Department of Molecular Cell Biology, University of Utrecht, Padualaan 8, 3584 CH Utrecht, The Netherlands.
authors.forename: P. P.
authors.initials: PP
authors.lastname: Dijkwel
authors.forename: PAM.
authors.initials: P
authors.lastname: Kock
authors.forename: R.
authors.initials: R
authors.lastname: Bezemer
authors.forename: P. J.
authors.initials: PJ
authors.lastname: Weisbeek
authors.forename: SCM.
authors.initials: S
authors.lastname: Smeekens