Termination of in vitro RNA Synthesis by Factor

A number of laboratories have demonstrated that during DNA-dependent RNA synthesis catalyzed by RNA polymerase release of RNA chains can occur. This release is dependent on the ionic strength of the RNA polymerase reaction mixture (Fuchs et al., 1967; So et al., 1967; Maitra and Barash, 1969; Richardson, 1970). Recently, Roberts (1969) discovered a protein called ρ, which causes release of RNA chains. These chains are considerably smaller in length than RNA found in its absence and for this reason it has been called a chain terminator. This paper will present evidence suggesting that release of RNA chains mediated by ρ factor and salt may be by different mechanisms.