Figure 4.

The 5′-deletion constructs with fused GUS reporter gene, uidA, and GUS reporter assays of transformants with each 5′-deletion construct of ptca1 promoter. Left, Schematics of 5′-deletion constructs of ptca1 promoter. The initial base of each construct is indicated in base pairs from the transcription start site (arrowheads in Fig. 3). The 5′-truncated ptca1 promoters were fused to uidA (accession no. S69414). Each construct was introduced into cells by microprojectile bombardment. Numbers of Zeocin-resistant (Zeo^r) clones and GUS-positive clones (GUS+) are indicated. Right, Levels of GUS activity measured in each GUS+ transformant grown in 5% CO₂ or air. GUS activities in lysates of 5% CO₂-grown transformants (white bars) and air-grown transformants (black bars) were determined per total protein bases. Ratios of GUS activity in air-grown cells to that in 5% CO₂-grown cells are indicated at the right of each black bar. N.D., Not detected; error bars, sd of three independent experiments.