Extended Data Fig. 4. Processivity of CST–Polα-primase on 9xTEL and 15xTEL templates; increasing DNA template concentration distinguishes processive C-strand synthesis from distributive re-priming.
a, Reaction of 25 nM CST–Polα-primase with increasing concentrations of 9xTEL or 15xTEL DNA template. b, Quantification of groups of extension products ('repeats') from a. Numbering of repeats is the same as in Fig. 1a. Increase of counts of repeat 1 products with increasing template concentration is interpreted as distributive re-priming, whereas the fraction of repeat 4 or 5 products that persists at high template concentration (1 µM template is 40-fold excess over concentration of CST–Polα-primase) is interpreted as processive extension. Repeat 4 is synthesized by approximately 70% re-priming and 30% processive synthesis. Products longer than repeat 4 are synthesized more by re-priming. Products shorter than repeat 4 persist at high [template], so they are due to processive extension from multiple initiation sites to the end of the template. For gel source data, see Supplementary Fig. 1