| Regulatory regions of DNA can be investigated
by placing those sequences into plasmid constructs upstream or in front
of a reporter gene. The level of expression of the gene is
then measured as a function of the DNA sequence. The E. coli
gene for the enzyme B-glucuronidase (GUS) is especially
useful as a reporter gene. This enzyme uses glucuronides as substrates.
Its advantage as a reporter gene for plants is that plants have virtually
undetectable levels of GUS. When plant cells expressing B-glucuronidase
are incubated with X-glucuronide (X-gluc) a blue colour is produced
that can be detected histochemically. |
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Hairy root of a rice plant
(non transformed control plant) after incubation in X-gluc |
Hairy root of a transgenic
rice plant expressing the GUS gene after incubation in X-gluc |
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