John Raasch asked about whether the 35S promoter was light regulated. I
used a 35S-GUS construct as a control in a study of the light-regulated
ferredoxin promoter (Plant Journal 3:161-174). We saw no evidence of
light activation of the 35S promoter in 5-day old etiolated seedlings given
24 h of light. Also, white light grown seedlings had the same GUS activity
as etiolated seedlings for 3 days. After that, the etiolated seedlings
actually had almost 2-fold higher GUS activity.