FIG. 1.

Summary of the functional regions identified in Tetrahymena telomerase RNA. The Tetrahymena RNA contains four helical regions, stem I to IV, and a conserved pseudoknot structure (brackets) (30). The specific helical regions are marked with a Roman numeral, and the nucleotide positions for each region are marked every 10 bases beginning at the 5′end. The template region is highlighted in yellow. A sequence conserved in ciliates that defines the template boundary is highlighted in green (1). This sequence overlaps with the defined tTERT-binding region shown in orange (19, 20). A region important for template utilization, the template-recognition element, is highlighted in blue (28).