title: RNA-linked nascent DNA pieces in phage T7-infected Escherchia coli. II. Primary structure of the RNA portion.
abstract: Short DNA chains were purified from phage T7 infected E. coli cells and 5' ends were labeled with 32P. By an alkali-treatment, pNp's rich in pAp and pCp were liberated from the T7 short DNA chains. After digestion of the [5'-32P] short DNA with the 3' to 5' exonuclease of T4 DNA polymerase, [5'-32P] mono- to pentaribonucleotides tipped with a deoxyribonucleotide residue at their 3' ends were isolated. 5' terminal ribonucleotides were; exclusively AMP in the penta- and the tetraribonucleotides, mostly CMP in the triribonucleotide and mainly CMP and AMP in di- and monoribonucleotides. The 5' terminal dinucleotide of the penta- and the tetraribonucleotides was pApC. The nucleotide sequence of the tetraribonucleotide was mainly pApCpCpN and some pApCpApN, where N was mainly A and C. These results indicate that oligoribonucleotides shorter than trinucleotide may result from in vivo degradation of the tetra- and pentaribonucleotides. A possibility that the tetra- and pentaribonucleotides with a 5' triphosphate terminus are the intact primers for the discontinuous T7 DNA replication is discussed.
mesh_terms: D001483:Base Sequence; D004261:DNA Replication; D004279:DNA, Viral / Q000096:biosynthesis*; D004926:Escherichia coli / Q000378:metabolism*; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization; D009843:Oligoribonucleotides / Q000032:analysis; D012367:RNA, Viral / Q000378:metabolism; D013604:T-Phages / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D009843:Oligoribonucleotides; D012367:RNA, Viral