Figure 4.

Rhythmic accumulation of total PHYA RNA and of all three PHYA transcripts. Seedlings were entrained for 2 weeks under 12-h light/12-h dark cycles. Tissue was harvested every 4 h following transfer to constant white light (white symbols) or during a further day of entrainment followed by darkness (black symbols). RNA was isolated and either total PHYA RNA or the three specific transcripts were measured by RNase protection assays. A, Accumulation of total PHYA RNA. B, The data for total PHYA RNA were normalized to ubiquitin RNA measurements; normalized values are plotted relative to the value at 8 h, when the samples are biologically equivalent. C, Accumulation of each of the PHYA RNA transcripts.