Molecular Biology of the Gene 7th Edition by Richard Losick, James Watson, Michael Levine, Tamara Baker, Alexander Gann

Exercise 2

You are studying the properties of an RNA polymerase ribozyme using a primer extension assay. This particular ribozyme has enhanced activity compared to a previous version of the ribozyme. The difference between the two ribozymes is that the enhanced ribozyme includes an additional domain at the 5? end. In each reaction of your primer extension, you include your ribozyme, your 5?-radiolabeled RNA primer bound to an RNA template, and rNTPs in the appropriate buffer. In reactions 2, you altered the sequence of the RNA template. In reaction 3, you altered the sequence of the RNA template and the sequence within the new domain of the ribozyme. You separate your products by denaturing polyacrylamide gel electrophoresis and visualize the bands on an autoradiograph (shown below).

A. Based on the data, describe the relative differences in ribozyme replicase activity between the three reactions.
B. Hypothesize why the products in lane 3 have a similar migration pattern as the products in lane 1.