In vitro studies of telomerase complexes derived from multiple organisms indicate that at least two types of interactions are important for telomerase RNP catalytic site alignment at the 3' G-rich single-strand telomere end. In one interaction, an alignment region in hTERC base-pairs with the 3' G-rich single-strand telomeric DNA end to form an RNA-DNA hybrid, which positions the template adjacent to the 3' end of the telomere. In a second interaction, a portion of hTERT is proposed to interact with the DNA 5' of the telomerase RNA/DNA primer hybrid (Harrington and Greider 1991; Morin 1991; Moriarty et al. 2005), which is important for the catalytic rate (Lee and Blackburn, 1993) and presumably allows telomerase to maintain contact with the chromosome during the translocation step. How the anchor site binding and template hybridization are coordinated is not known.