Disclosed is an isolated RNA molecule comprising: a) an alphavirus 5 replication recognition sequence, wherein at least one initiation codon has been removed from the 5 replication recognition sequence b) a nucleotide sequence encoding an alphavirus structural protein and c) an alphavirus 3 replication recognition sequence, with the proviso that the RNA molecule does not contain a promoter that directs transcription of the nucleotide sequence of (b), and wherein the alphavirus 5 and 3 replication recognition sequences of (a) and (c) direct replication of the RNA molecule in the presence of alphavirus nonstructural proteins.
