C. Godon et al., USE OF THE BIOLISTIC PROCESS FOR THE ANALYSIS OF NITRATE-INDUCIBLE PROMOTERS IN TRANSIENT EXPRESSION ASSAYS, PLANT SCI, 111(2), 1995, pp. 209-218
The expression of reporter genes under the control of nitrate reductas
e or nitrite reductase promoters measured in bombarded leaf tissues wa
s compared to transcript levels expressed from the resident Nia gene o
r to that of a reporter gene under the control of nitrite reductase pr
omoter stably inserted into the nuclear genome. It was found that tran
sient assays do not reflect the expression of the genomic integrated s
equences. Particularly striking was the absence of repression of the r
eporter genes by ammonium or glutamine in transient assays. The limits
of the use of particle bombardment in transient experiments are discu
ssed. One of the different hypotheses explaining the data involved a m
odel of a negative control mediating the repression of Nia and Nii gen
es expression on reduced nitrogen source.