Figure 4.

Activation of the CBF1, 2, and 3 promoters in response to low temperatures. Representative transgenic lines of Arabidopsis carrying the CBF1, 2, or 3 promoter fused to the GUS reporter gene were transferred from 22°C (W) to 4°C (C) for 2 h. The transcript levels of the gene fusions were determine using a probe for the GUS sequences.