Authors : K. DUTTA, M. BELJANSKI, P. BOURGAREL
Botany Department, Howard University, Washington, DC
Exp. Mycology, 1977, 1, pp. 173-182.
Available in English only
ABSTRACT: Evidence indicating the presence of a RNA-bound RNA-dependent DNA polymerase (RDDP) in the eukaryotic fungus Neurospora crassa is presented. This enzyme, free of DNA-dependent DNA polymerase, is capable of synthesizing DNA only in the presence of all four deoxyribonucleoside 5′-triphosphates and Mg2+. The DNA polymerase activity is decreased considerably if the RNA bound to the enzyme is eliminated. The activity can be restored by addition of some particular RNA but not by addition of DNA. Both template RNA and the synthesized DNA product sedimented on sucrose density gradients are approximately 6 S. RNA-bound RNA-dependent DNA polymerase partially purified from extracts of N. crassa was distinguishable from known DNA-dependent DNA polymerases. DNA synthesized by RDDP was acid-precipitable and complementary to enzyme-bound RNA.