ISOLATION AND PROMOTER CHARACTERIZATION OF BARLEY GENE ITR1 ENCODING TRYPSIN-INHIBITOR BTI-CME - DIFFERENTIAL ACTIVITY IN WILD-TYPE AND MUTANT LYS3A ENDOSPERM
J. Royo et al., ISOLATION AND PROMOTER CHARACTERIZATION OF BARLEY GENE ITR1 ENCODING TRYPSIN-INHIBITOR BTI-CME - DIFFERENTIAL ACTIVITY IN WILD-TYPE AND MUTANT LYS3A ENDOSPERM, Plant molecular biology, 31(5), 1996, pp. 1051-1059
The gene Itr1, encoding trypsin inhibitor BTI-CMe, has been obtained f
rom a genomic library of Hordeum vulgare L. The gene has no introns an
d presents in its 5'-upstream region 605 bp that are homologous to the
long terminal repeats (LTR) of the 'copia-like' retro-transposon Bare
-1. Functional analysis of the Itr1 promoter by transient expression i
n protoplasts derived from different barley tissues, has shown that in
this system the Itr1 promoter retains its endosperm specifity and the
trans-regulation mediated by the Lys3a gene. The proximal promoter ex
tending 343 bp upstream of the translation initiation ATG codon is suf
ficient to confer full GUS expression and for endosperm specifity. In
protoplasts derived from the lys3a mutant, Riso1508, GUS activity was
less than 5% of that obtained with the same constructs in the protopla
sts of wild-type Bomi from which it derives. Gel retardation experimen
ts, after incubation with proteins obtained from both types of endospe
rm nuclei, also show differential patterns. Possible reasons for these
differences are discussed.