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B G Barrell

Publications and source records attributed to B G Barrell.

At least 91 records · Page 5Linked to original sources

Nucleotide sequences of the separate origins of synthesis of bacteriophage G4 viral and complementary DNA strands.

Bacteriophage G4 has physically separated origins of synthesis of its viral and complementary DNA strands. Chain termination and "plus and minus" DNA sequencing methods have been used to obtain the nucleotide sequence of these two origins. The unique origin at which the complementary DNA strand is initiated has located in the untranslated region between genes F and G. This sequence, which has considerable secondary structure, contains a stretch which is complementary to the RNA primer that is observed during synthesis in vitro of the G4 complementary DNA strand [Bouché, J.P., Rowen, L. & Kornberg, A. (1978) J. Biol. Chem., in press]. This G4 origin shows extensive sequence homology with the bacteriophage lambda origin of DNA replication [Denniston-Thompson, K., Moore, D. D., Kruger, D. E., Furth, M. E. & Blattner, F. R. (1977) Science 198, 1051-1056]. The sequence around the site in gene A at which G4 viral DNA strand synthesis is initiated by the nicking action of the cistron A protein is very similar to that of bacteriophage phiX174. An (A + T)-rich stretch flanked by (G + C)-rich sequences may be involved in the interaction between the DNA and protein.

Bacteriophages↗

Nucleotide sequence of bacteriophage phi X174 DNA.

A DNA sequence for the genome of bacteriophage phi X174 of approximately 5,375 nucleotides has been determined using the rapid and simple 'plus and minus' method. The sequence identifies many of the features responsible for the production of the proteins of the nine known genes of the organism, including initiation and termination sites for the proteins and RNAs. Two pairs of genes are coded by the same region of DNA using different reading frames.

Base Sequence↗

The use of primed synthesis by DNA polymerase I to study an intercistronic sequence of phiX-174 DNA.

A decadeoxynucleotide complementary to ten nucleotides in the major ribosome-protected fragment of phiX-174 plus-strand DNA has been chemically synthesized and used as a primer for DNA polymerase I on phiX-174 plus-strand DNA as template. The sequence of the first 40 nucleotides incorporated onto the decadeoxynucleotide has been determined. This sequence extends further the sequence of the intercistronic region preceding gene G and shows the presence of another termination codon. The sequence was determined by using manganese as the activating cation for DNA polymerase I which allows ribonucleotides to be incorporated as well as deoxyribonucleotides. The ribo-substituted product was then cleaved specifically at the ribonucleotide residues to generate a series of overlapping ribo-terminated fragments whose sequences were sufficient to determine the complete sequence of the first 40 nucleotides. No evidence for misincorporation by DNA polymerase I in the presence of manganese was detected.

Adenosine Triphosphate↗

Transfer RNA biosynthesis: the nucleotide sequence of a precursor to serine and proline transfer RNAs.

The nucleotide sequence of a transfer RNA precursor molecule coded by bacteriophage T4 has been determined. The molecule is a single polynucleotide chain which contains two transfer RNA species that are destined to recognize serine and proline. The 3' -CCA(OH) termini of both mature transfer RNA species are absent in the precursor molecule; these termini must therefore be added enzymatically at a subsequent stage of maturation. Nucleotide residues unique to the precursor are located at both ends of the molecule and between the two transfer RNA sequences.

Base Sequence↗

Nucleotide sequences of two fragments from the coat-protein cistron of bacteriophage R17 ribonucleic acid.

Bacteriophage R17 RNA was labelled with (32)P and was subjected to partial digestion with ribonuclease T(1). The products were fractionated by ionophoresis on polyacrylamide gel. Two fragments were purified and their nucleotide sequences determined by methods involving complete and further partial digestion with ribonucleases A and T(1). Fragment 20 had a sequence that coded for the amino acids in positions 32-53 of the coat protein of the bacteriophage. Fragment 20X, on further purification in 7m-urea, gave rise to two smaller nucleotides whose sequences coded for the amino acids in positions 56-66 and 67-76 of the coat protein. The sequence of the two fragments was such that they could be written in the form of loops stabilized by base-pairing.

Acrylates↗

Eight transfer RNAs induced by infection of Escherichia coli with bacteriophage T4.

Bacteriophage T4 induces the synthesis of eight transfer RNAs upon infection of E. coli. The tRNAs are easily detected and resolved into pure species by polyacrylamide gel electrophoresis of RNA labeled with (32)P after T4 infection. Two-dimensional fingerprints of RNase T(1) products derived from individual gel bands give patterns characteristic of single tRNAs. Furthermore, the T(1) digest of each gel band has a single oligonucleotide that contains the minor nucleotides Tp and Psip, a characteristic feature of all known tRNAs. Four larger RNAs are also seen in the polyacrylamide gels. Fingerprint and genetic analyses demonstrate that these molecules are related to the tRNAs, but the exact nature of this relationship is not known.

Base Sequence↗