Telomerase reverse transcriptase is part of the telomerase complex responsible for maintaining telomere length and increasing the replicative capacity of progenitor cells. Telomerase activity is turned off in mature differentiated cells, but is turned back on again in hyperplastic diseases, including many cancers. This disclosure provides regulatory elements that promote transcription in cells that express telomerase reverse transcriptase (TERT). The disclosure also provides systems using TERT promoter sequences for identifying compounds that can be used to modulate telomerase expression.