Plant Molecular Biology 44: 747–758, 2000.
© 2000 Kluwer Academic Publishers. Printed in the Netherlands.
Spatial and temporal patterns of GUS expression directed by 5
the Arabidopsis thaliana farnesyl diphosphate synthase genes FPS1 and
, Albert Boronat
and Albert Ferrer
Departament de Bioqu´ımica i Biologia Molecular, Facultat de Farm`acia, Universitat de Barcelona, Av. Diagonal
643, 08028-Barcelona, Spain (
author for correspondence; e-mail: email@example.com);
de Bioqu´ımica i Biologia Molecular, Facultat de Qu´ımica, Universitat de Barcelona, Mart´ı i Franqu`es 1, 08028-
Received 18 April 2000; accepted in revised form 15 August 2000
Key words: Arabidopsis thaliana, β-glucuronidase (GUS) reporter gene, farnesyl diphosphate synthase, gene
expression, isoprenoids, transgenic plants
Farnesyl diphosphate synthase (FPS), the enzyme that catalyses the synthesis of farnesyl diphosphate (FPP) from
isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), is considered a regulatory enzyme of
plant isoprenoid biosynthesis. The promoter regions of the FPS1 and FPS2 genes controlling the expression of
isoforms FPS1S and FPS2, respectively, were fused to the β-glucuronidase (GUS) reporter gene and introduced
into Arabidopsis thaliana plants. The FPS1S:GUS gene is widely expressed in all plant tissues throughout de-
velopment, thus supporting a role for FPS1S in the synthesis of isoprenoids serving basic plant cell functions.
In contrast, the FPS2:GUS gene shows a pattern of expression restricted to speciﬁc organs at particular stages
of development. The highest levels of GUS activity are detected in ﬂowers, especially in pollen grains, from the
early stages of ﬂower development. After pollination, much lower levels of GUS activity are detected in the rest of
ﬂoral organs,with the exceptionof the ovary valves, which remain unstained throughoutﬂower development. GUS
activity is also detected in developing and mature seeds. In roots, GUS expression is primarily detected at sites of
lateral root initiation and in junctions between primary and secondary roots. No GUS activity is detected in root
apical meristems. GUS expression is also observed in junctions between primary and secondary stems. Overall,
the pattern of expression of FPS2:GUS suggests a role for FPS2 in the synthesis of particular isoprenoids with
specialized functions. Functional FPS2 gene promoter deletion analysis in transfected protoplasts and transgenic
A. thaliana plants indicate that all the cis-acting elements required to establish the full pattern of expression of the
FPS2 gene are contained in a short region extending from positions −111 to +65. The potential regulatory role of
speciﬁc sequences within this region is discussed.
Abbreviations: bZIP, basic leucine zipper; DMAPP, dimethylallyl diphosphate; FPP, farnesyl diphosphate; FPS,
farnesyl diphosphate synthase; GUS, β-glucuronidase; IPP, isopentenyl diphoshate; LUC, luciferase; PCR,
polymerase chain reaction.
Farnesyl diphosphate synthase (FPS; dimethylallyl-
transtransferase, EC 22.214.171.124/geranyltranstransferase,
EC 126.96.36.199) catalyzes the synthesis of farnesyl
diphosphate (FPP) by the head-to-tail condensation of
dimethylallyl diphosphate (DMAPP) and two mole-
cules of isopentenyl diphosphate (IPP). Although the