FIG. 9.

Scheme for primer elongation by telomerase based on the footprinting data. A structural element in the telomerase, which is schematically illustrated as a cylinder and designated the TDIS, strongly interacts with the six or seven 3′-terminal nucleotides in the primers. As the primers are elongated, TDIS moves in concert with their 3′ termini along the template region in the telomerase RNA (see the Discussion). g and t are newly added oligonucleotides (Fig. 1).