RNA-Catalyzed RNA Polymerization: Accurate and General RNA-Templated Primer Extension
Wendy K. Johnston,
Peter J. Unrau,*
Michael S. Lawrence,
Margaret E. Glasner,
David P. Bartel
The RNA world hypothesis regarding the early evolution of life
relies on the premise that some RNA sequences can catalyze RNA
replication. In support of this conjecture, we describe here an RNA
molecule that catalyzes the type of polymerization needed for RNA
replication. The ribozyme uses nucleoside triphosphates and the coding
information of an RNA template to extend an RNA primer by the
successive addition of up to 14 nucleotides--more than a complete turn
of an RNA helix. Its polymerization activity is general in terms of the
sequence and the length of the primer and template RNAs, provided that
the 3' terminus of the primer pairs with the template. Its
polymerization is also quite accurate: when primers extended by 11 nucleotides were cloned and sequenced, 1088 of 1100 sequenced
nucleotides matched the template.
Whitehead Institute for Biomedical Research, and Department of
Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
*
Present address: Department of Molecular Biology and
Biochemistry, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada.
To whom correspondence should be addressed. E-mail:
dbartel{at}wi.mit.edu
