Figure 1. Strategy to Identify Temporal Regulatory Elements.

(A) Flowchart of the strategy used.

(B) Northern blot of pha-4. pha-4 transcripts were approximately 25- to 100-fold enriched in par-1 compared to skn-1 embryos, but only approximately 5- to 10-fold enriched in wild-type compared to skn-1 embryos. Arrowheads indicate the three different pha-4 isoforms.

(C) The same blot was probed with a fragment of the act-1 gene to demonstrate equal loading of RNA between lanes.