RNA-linked nascent DNA pieces in phage T7-infected Escherichia coli. III. Detection of intact primer RNA.
RNA-linked DNA fragments of T7-infected Escherichiacoli were labeled with [(32)P]orthophosphate invivo. The RNA segments of the labeled fragments were isolated by degrading the DNA portion with the 3'--> 5' exonuclease intrinsic to bacteriophage T4 DNA polymerase and fractionated according to net charge by a DEAE-Sephadex A-25 column chromatography in the presence of 7 M urea. Tri-, tetra- and pentanucleotides were obtained which have ATP residues at their 5' ends. Most of the pentanucleotides had a single deoxynucleotide at the 3' end but a minor portion was totally an oligoribonucleotide. In the light of prior results, the former is a cooligomer of an intact tetraribonucleotide primer and a monodeoxynucleotide and the latter is an intact pentaribonucleotide primer. Tri- and tetraribonucleotides with ATP at the 5' ends had no deoxynucleotide at the 3' ends, therefore it is not clear if intact triribonucleotide primers are present. The 5'-terminal dinucleotides of the tetra- and pentanucleotides were mostly pppApC and a trace amount of pppApA was present.Images
D001483:Base Sequence; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D005092:Exonucleases / Q000378:metabolism; D009843:Oligoribonucleotides / Q000032:analysis; D012367:RNA, Viral / Q000378:metabolism; D013604:T-Phages / Q000378:metabolism*; D014779:Virus Replication
D004279:DNA, Viral; D009843:Oligoribonucleotides; D012367:RNA, Viral; D004259:DNA-Directed DNA Polymerase; D005092:Exonucleases