The promoter of a cytosolic glutamine synthetase gene from the conifer Pinus sylvestris is active in cotyledons of germinating seeds and light-regulated in transgenic Arabidopsis thaliana.
We have isolated and characterized a genomic clone encoding Scots pine (Pinus sylvestris) cytosolic glutamine synthetase (GS). The clone contains the 5' end half of the gene including part of the coding region and 980 bp upstream of the translation initiation codon. The major transcription start site (+1) was mapped around 180 nucleotides upstream of the translation initiation codon. Sequence analysis of the 5'-upstream region of the gene reveals the presence of putative regulatory elements including a poly-CT consensus sequence, a purine-rich tandem repeat and two AT-rich regions. Fusions of the upstream gene region to uidA were shown to be transiently expressed in the cotyledons of germinating pine seeds transformed by microprojectile bombardment. Stable transformation of Arabidopsis thaliana revealed the shoot apical meristem as the major region of heterologous permanent expression in Arabidopsis, in agreement with the expression of the GS gene in Pinus. Moreover, quantitative data derived from fluorometric beta-glucuronidase assays in control and continuous light-grown transgenic Arabidopsis plants indicate that the isolated upstream region of the gene contains regulatory sequences involved in the response to light.
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Concepción
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Departamento de Biología Molecular y Bioquímica, Instituto Andaluz de Biotecnología, Unidad Asociada UMA-CSIC, Universidad de Málaga, E-29071, Málaga, Spain; Laboratorio Fisiología y Biotecnología Vegetal, Facultad de Ciencias, Universidad de Vigo, E-36200, Vigo, Spain; Laboratorio Fisiología Vegetal, Departamento BOS, Universidad de Oviedo, E-33071 Oviedo, Spain.
R Cantón
Francisco
F
Barnestein
Pilar
P
Suárez
María-Fernanda
MF
Marraccini
Pierre
P
Rey
Manuel
M
Humara
Jaime M.
JM
Ordás
Ricardo
R
M Cánovas
Francisco
F