7 research outputs found
Development and characterization of a chimaeric tissue-specific promoter in wheat and rice endosperm
The recently achieved significant improvement of cereal transformation
protocols provides facilities to alter the protein composition of the
endosperm, for example, to increase or decrease the quantity of one of
its protein components or to express foreign molecules. To achieve this
goal, strong endosperm-specific promoters have to be available. The aim
of our work was to develop a more efficient tissue-specific promoter
which is currently used. A chimaeric promoter was assembled using the
5' UTR (1,900 bp) of the gene coding for the 1Bx17 HMW glutenin subunit
protein, responsible for tissue-specific expression and the first
intron of the rice actin gene (act1). The sequence around of the
translation initial codon was optimized. The effect of the intron and
promoter regulatory sequences, using different lengths of 1Bx17 HMW-GS
promoter, were studied on the expression of uidA gene. The function of
promoter elements, promoter length, and the first intron of the rice
actin gene were tested by a transient expression assay in immature
wheat endosperm and in stable transgenic rice plants. Results showed
that insertion of the rice act1 first intron increased GUS expression
by four times in transient assay. The shortest 1Bx17 HMW-GS promoter
fragment (173 bp) linked to the intron and GUS reporter gene provided
almost the same expression level than the intronless long 1Bx17 HMW-GS
promoter. Analysis of the stable transformant plants revealed that 173
nucleotides were sufficient for endosperm-specific expression of the
uidA gene, despite 13 nucleotides missing from the HMW enhancer
sequence, a relevant regulatory element in the promoter region