The nucleotide sequence of two restriction fragments located in the gene AB region of bacteriophage S13

Nucleotide sequence and genome organization of bacteriophage S13 DNA

The complete sequence of bacteriophage S13 DNA has been determined. The molecule has 5386 nucleotides and differs from phi X174 by 87 transitions and 24 transversions. All the proteins, A,A*,B,C,D,E,F,G,H, J and K found in phi X174 are also present in S13. Due to changes in the H/A intergenic region of S13, the start of an additional protein, A', has been identified. Genes F and H coding for the capsid and spike proteins, respectively, are the least conserved in comparison to phi X174. Many of the silent changes, as well as some amino acid changes, are found in the same nucleotide sequence positions in phage G4, confirming the interrelationship between the three phages.

Sequence studies on mouse L-cell satellite DNA by base-specific degradation with T4 endonuclease IV

The base sequence of mouse L-cell satellite DNA was investigated by degradation of the two separated complementary strands with the base specific enzyme, T4 endonuclease IV. Digestion of the heavy strand DNA released a limited number of oligonucleotides which were separated by ionophoresis/homochromatography, isolated, and sequenced by the 'wandering spot' method. The light strand DNA was resistant to digestion with T4 endonuclease IV and no detectable amounts of oligonucleotides were released. The oligonucleotides obtained from the heavy strand were related in sequence, indicating that mouse satellite DNA derived from a short tandemly repeated sequence. The sequence of part of the original repeat unit is proposed to be C-A-T-T-T-T-T-C. Five major oligonucleotides were identified, all of which differ from the proposed original sequence by single base changes. The five major oligonucleotides occur with about equal frequency and together comprise approximately 50% of the oligonucleotides released by T4 endonuclease IV from the heavy strand DNA. In addition to the five major oligonucleotides, several oligonucleotides were found to occur in lesser amounts. Since these oligonucleotides are related to the major oligonucleotides, it is likely that they have arisen from them by mutation.

Localization of Escherichia coli RNA polymerase binding sites on bacteriophage S13 and phiX174 DNA: alignment with restriction enzyme maps

Escherichia coli RNA polymerase has been shown to bind to a limited number of Hind and Hae III restriction enzyme fragments. On S13 replicative form DNA there are three major binding sites, and the locations correlate with promoter sites at the beginning of genes a and B and a site overlapping gene D and the beginning of gene E. Two less definite binding sites have been localized, one in gene F and one at the gene G-H junction. In phiX174 replicative form DNA, five sites, each with apparently similar binding properties, have been located, four of which correspond exactly to binding sites in S13. One site, at the beginning of the B gene, could not be assigned to exactly the same location found in S13. This was due in part to differences in the restriction cleavage maps in the area of the DNA and possibly to the higher background of nonspecific binding in the phiX174 experiments. The location of two of the phiX174 sites at the beginning of genes A and D-E corresponds very well with transcription data, but the site at the start of the B gene indicates the promoter site is closer to the initiation sequence of the B protein than was previously suggested on the basis of transcription data.