Thousands of genes are affected by elevated intracellular calcium. Venn diagrams show the intersection of potassium chloride (KCl) and thapsigargin (TPG) transcript and exon datasets. Indicated in bold are the number of transcripts in each dataset. All significantly changing transcripts identified in the KCl time course are represented. A subset of transcripts were scored as changing in abundance, even though individual exons within these transcripts were not scored as showing statistically significant changes in expression levels. This is a statistical artifact that results from using data from only a few probes per exon (typically four), but many more probes per transcript. See Materials and methods. Light blue indicates KCl whole transcript changes, and dark blue indicates transcripts that display a change in exon abundance upon KCl. Dark red indicates TPG whole transcript changes, and light red indicates transcripts that display a change in exon abundance upon TPG. Identification of early growth-response factor 1 (EGR1) and X-box binding protein 1 (XBP1) in specific datasets is indicated.