Examples of eRNA peaks near Sp-jun. (A) Three of the four eRNA peaks shown (top track; gray bars) overlap with chromatin regions that are hyperaccessible at 24 hpf but not at the 128-cell stage, as determined by ATAC-seq and DNase-seq (Shashikant et al. 2018). (B) Temporal CAGE-seq coverage tracks illustrate the bidirectional expression of eRNAs and the very low abundance of eRNA reads relative to coding genes (scale: zero to three read counts). Sea urchin jun is expressed at high levels maternally, followed by a second peak of expression at gastrula stage. Spatially, jun is distributed homogenously in unfertilized egg and during early cleavages and is restricted to the PMCs at later stages (Russo et al. 2014).
