Fig. 2.

Speed of the transcription wave on ZFPM2. (A) Decay of RNA. Sum total signals given by all probes in 1,000 base windows between 15 and 180 min was calculated and shown by red bars (height reflects intensity). Blue lines were obtained by linear regression (slope indicated in each intron), showing that signal declines to zero from beginning to end of each intron. (B) Speed of wave front. For each probe on the tiling array, a blue dot indicates where expression first reaches 50% of the maximum (using 40–70% of the maximum yields similar velocities; Fig. S3), and we use this to define the wave front. A red dot marks the average position of all blue dots at one time point. The velocity of the wave front was calculated by linear regression using the red dots (red line). Vertical axis shows time after stimulation. Genomic location is shown on top of each column. Direction of the gene is shown by the arrow.