Nucleotide sequences in the DNA preceeding the site of initiation of lambda 6S RNA and following the site of termination of vitro transcription, in adenovirus DNA preceeding the site of initiation of VA RNA and following the termination of transcription of VA RNA will be determined. Studies will be continued to compare the nucleotide sequences of other RNA polymerase promotors with that already determined for E. coli polymerase in SV40 DNA. Nucleotide sequences about the site of initiation of the replication of DNA in SV40 viruses will be determined.