Template specificity of Qbeta and SP phage RNA replicases as studied by replication of small variant RNAs. |
| |
Authors: | Yasuo Fukami and Ichiro Haruna |
| |
Institution: | (1) Department of Biology, Faculty of Sciense, Osaka University, 560 Toyonaka, Osaka, Japan;(2) Present address: Department of Preventive Medicine, Research Institute for Microbial Diseases, Osaka University, 565 Suita city, Osaka, Japan |
| |
Abstract: | Summary Template specificity of two RNA-dependent RNA polymerases (Q and SP RNA replicases) was examined using variant RNAs as template. Three variant RNAs, one (8S) generated by Q replicase and two (6S and 5.2S) generated by SP replicase, were isolated from the reaction mixtures incubated in the absence of exogenous template RNA. All these RNAs were found to be active as template for both Q and SP replicases, though homologous RNA exhibited activities about three times higher than heterologous RNA with either enzyme, in agreement with the results obtained in phage RNA-dependent reactions. In these reactions, faithful replication of variant RNA was observed, and the amount of RNA synthesized was in a many-fold excess over the template RNA added. We also found that the heterologous RNA-dependent reactions were suppressed by increasing the concentration of salts or decreasing the concentration of substrates. Under such conditions, replication of heterologous variant RNA was almost completely suppressed, while the amount of homologous variant RNA synthesized was only reduced to 50% of that synthesized under the standard conditions. Thus the template specificity of the two RNA replicases seems to be expressed more strictly in these replication systems.Deceased |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|