The body TRS is a better candidate to serve as a protein recognition site. This protein would then mediate the pausing of the nascent strand synthesis and/or nascent strand transfer. This would resemble the DNA-dependent RNA polymerase I termination system, in which speci®c DNA-binding terminator proteins bind to termination sequences (Reeder and Lang, 1997) , or a function of the HIV nucleocapsid protein, which promotes the minus strand strong-stop DNA transfer (Guo et al., 1997) . The EAV replicase component nsp1, which recently was shown to possess an sg RNA synthesis-speci®c activity (Tijms et al., 2001) , may be a good candidate for such a regulatory role. Residues predicted to form a zinc ®nger structure in nsp1 were shown to be necessary for sg RNA synthesis. Interestingly, zinc ®nger structures in the HIV nucleocapsid protein facilitate strand transfer (Guo et al., 2000) . Finally, it should be noted that the RNA structure of the nascent strand may also in¯uence pausing, strand transfer or reinitiation, as illustrated by the fact that stable hairpin structures in the nascent strand promote termination of transcription by Escherichia coli RNA polymerase (Wilson and von Hippel, 1995) .