An RNA transcribed from DNA at the origin of phage fd single strand to replicative form conversion.

Phage fd DNA complexed with DNA binding protein I was used by Escherichia coli RNA polymerase (nucleoside triphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) to synthesize an RNA at the origin of single strand to double strand replication. The isolated ori-RNA gave a simple fingerprint after nucleolytic digestion and has a length of about 30 nucleotides. The characterization of the oligonucleotides from the nuclease digest and the extension of the ori-RNA with DNA polymerase I and subsequent restriction of the DNA gave its exact localization in the fd genome, and its total sequence was deduced from the known DNA sequence in this region.