Plant Molecular Biology 34: 837–842, 1997.
1997 Kluwer Academic Publishers. Printed in Belgium.
Cloning and characterization of elongation speciﬁc endo-1,4-
(cel1) from Arabidopsis thaliana
Ziv Shani, Mara Dekel, Galit Tsabary and Oded Shoseyov
The Kennedy Leigh Centre for Horticultural Research and The Otto Warburg Center for Agricultural
Biotechnology. The Faculty of Agriculture, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76100,
author for correspondence)
Received 9 July 1996; accepted in revised from 25 February 1997
Key words: elongation, gene expression, glucanase, Arabidopsis thaliana
The isolation of an elongation-speciﬁc endo-1,4-
-glucanase-cel1 from Arabidopsis thaliana was made possible
bythefactthat considerablehomologyexists between differentendo-1,4-
RNA transcripts were undetectable in fully expanded leaves as well as at the basal internode of ﬂowering stems.
However, a strong transcript signal was detected in the elongating zone of ﬂowering stems of normal plants.
The RNA transcript level of cel1 in the elongating zone of dwarf ﬂowering stems was signiﬁcantly lower than
in the corresponding zone in normal plants. This suggests cel1’s involvement in cell elongation in A. thaliana.
Transgenic tobacco plants transformed with the putative cel1 promoter region fused to the gus reporter gene,
showed a signiﬁcant GUS staining both in shoot and root elongating zones. These results further substantiate the
link between cel1 expression and plant cell elongation.
The plant cell elongation mechanism is a fundamen-
tal process with primary importance in plant-tissue
rigid primary cell wall [2, 5, 10, 26]. Several mecha-
nisms for this relaxation have been suggested, includ-
ing the activities of endoxyloglucan transferase ,
xyloglucan endotransglycosylase  and expansins
. EGase has been suggested to play an important
role in the elongation process [29, 34]. Substantional
evidence for the involvement of a 1,3-1,4-
speciﬁc enzyme in cell elongationwas found in mono-
cotyledons [13, 17, 18]. EGase has been implicated in
xyloglucan degradation during vegetative growth and
fruit ripening [14, 15]. The activity of this enzyme
Thenucleotidesequencedatareportedwill appear in theEMBL,
GenBank and DDBJ Nucleotide Sequence Databases under the
accession numbers X98543 and X98544.
could affect the generation of oligosaccharins, signal-
ing moleculesthat are involved,amongother things, in
plant development and cell elongation (see for review
). Most of the EGase genes isolated to date have
been studied in relation to fruit ripening [3, 9, 23,
31] and abscission zones [21, 32, 33]. More recent-
ly, Wu et al.  cloned the EGase gene from pea
and showed its expression to be induced by auxin in
elongating epicotyls. In the present work we describe
the cloning and characterizationof elongation-speciﬁc
EGase (cel1) from A. thaliana.
Materials and methods
Plant material and isolation of plant nucleic acids
Arabidopsis thaliana cv. Columbia and Nicotiana
tabaccum-SR1 plants were grown at 24