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Biomedical subjects

B G Barrell

Publications and source records attributed to B G Barrell.

At least 73 records · Page 4Linked to original sources
PubMed1985

Cloning, characterization, and sequence of the yeast DNA topoisomerase I gene.

The structural gene for yeast DNA topoisomerase I (TOP1) has been cloned from two yeast genomic plasmid banks. Integration of a plasmid carrying the gene into the chromosome and subsequent genetic mapping shows that TOP1 is identical to the gene previously called MAK1. Seven top1 (mak1) mutants including gene disruptions are viable, demonstrating that DNA topoisomerase I is not essential for viability in yeast. A 3787-base-pair DNA fragment including the gene has been sequenced. The protein predicted from the DNA sequence has 769 amino acids and a molecular weight of 90,020.

Base Sequence↗
PubMed1985

Two related but differentially expressed potential membrane proteins encoded by the EcoRI Dhet region of Epstein-Barr virus B95-8.

Three mRNAs in the EcoRI Dhet region of Epstein-Barr virus B95-8 were mapped. Their 3' ends are coterminal. A latent gene containing three exons is transcribed from the ED-L1 promoter and was predicted to lead to expression of a 42-kilodalton protein. An unspliced late mRNA is produced by transcription from the ED-L1A promoter within the first intron of the above gene and was predicted to lead to expression of a 28-kilodalton protein corresponding to the C-terminal two-thirds of the 42-kilodalton protein. Both proteins would have hydrophobic N-terminal domains and highly acidic C-terminal domains and were predicted to span the cell membrane. An early promoter (ED-L2) is located in the 3' untranslated region of the above genes and was predicted to lead to expression of a 6.5-kilodalton polypeptide containing a C-terminal hydrophobic region.

Base Sequence↗
PubMed1985

Terminal repetitive sequences in herpesvirus saimiri virion DNA.

The H-DNA repeat unit of Herpesvirus saimiri strain 11 was cloned in plasmid vector pAGO, and the nucleotide sequence was determined by the dideoxy chain termination method. One unit of repetitive DNA has 1,444 base pairs with 70.8% G+C content. The structural features of repeat DNA sequences at the termini of intact virion M-DNA (160 kilobases) and orientation of reiterated DNA were analyzed by radioactive end labeling of M-DNA, followed by cleavage of the end fragments with restriction endonucleases. The termini appeared to be blunt ended with a 5'-phosphate group, probably generated during encapsidation by cleavage in the immediate vicinity of the single ApaI recognition site in the H-DNA repeat unit. The sequence did not reveal sizeable open reading frames, the longest hypothetical peptide from H-DNA being 85 amino acids. There was no evidence for an mRNA promoter or terminator element, and H-DNA-specific transcription could not be found in productively infected cells.

Animals↗
PubMed1984

Transcription and DNA sequence of the BamHI L fragment of B95-8 Epstein-Barr virus.

The sequence of the BamHI L fragment of B95-8 Epstein-Barr virus (EBV) DNA has been determined. The transcription starts of five promoters have been mapped to this fragment, using S1 mapping and either in vitro transcription or the primer extension technique. Dramatically increased levels of cytoplasmic poly(A) + RNAs, transcribed from these promoters, occur after treatment of B95-8 cells with 12-O-tetradecanoylphorbol-13-acetate (TPA). For three of these promoters addition of phosphonoacetic acid (PAA) inhibits the effect of TPA, indicating that they give rise to late lytic cycle RNAs. The other two promoters give rise to early RNAs. Northern blot analysis indicates that one of the late promoters initiates two transcripts whose size differences are due to different splicing patterns. These two RNAs code for the 350/300 and 250/200 kd envelope glycoproteins of EBV. The sequences of these proteins would be of use in the production of a synthetic vaccine to prevent EBV infection.

Animals↗
PubMed1983

Latent and lytic cycle promoters of Epstein-Barr virus.

Four RNA polymerase II promoters have been mapped in the DNA sequence of the EcoRI-H and -Dhet fragments of B95-8 Epstein-Barr virus. RNAs transcribed from three of these promoters are dramatically induced by treatment of B95-8 cells with 12-O-tetradecanoylphorbol-13-acetate (TPA). The other promoter is active with or without TPA treatment of the cells and is thus active in the latent virus cycle. Deletion mapping suggests that DNA sequence homologies between some of the promoters lie in the same region as essential upstream promoter elements.

Base Sequence↗
PubMed1983

Sequence analysis of the 17,166 base-pair EcoRI fragment C of B95-8 Epstein-Barr virus.

In order to provide a framework for understanding the molecular biology of Epstein-Barr virus (EBV), we are determining the DNA sequence of the virus and studying the organization of genes on the viral genome. In this paper we report the DNA sequence of the EcoRI C fragment of the B95-8 strain of EBV. The large (approximately 13.6 kb) deletion in this strain has been located by comparison with the DNA sequence of EBV isolated from Raji cells. The sequence has been analysed for possible protein coding regions and transcriptional control sites. At least eight large open reading frames are found, some of them associated with canonical promoter and polyadenylation sequences. The sequences of some of the encoded proteins suggest that they are membrane proteins. It is known that antibodies to major membrane glycoproteins of EBV can neutralize infection in tissue culture. A possible relationship between some of the encoded proteins and the major membrane glycoproteins of the virus is discussed.

Base Sequence↗
PubMed1983

Nucleotide sequence of the transforming region of human cytomegalovirus.

We report the nucleotide sequence of a BamHI-HindIII fragment of human cytomegalovirus containing the region (XbaI-HindIII) capable of transforming NIH3T3 cells. The single EcoRI site, shown to abolish transforming activity if cleaved, is present within an 8 base-pair inverted complementary repeat. Close to this sequence there is a small, potentially spliced, open reading frame possessing some of the signals involved in eukaryotic gene expression. Possible mechanisms of transformation, involving the inverted repeat sequence, are discussed.

Base Sequence↗
PubMed1983

DNA sequence and transcription of the BamHI fragment B region of B95-8 Epstein-Barr virus.

The DNA sequence of the BamHI fragments B and the contiguous portion of G extending from the BamHI site to the EcoRI site of the B95-8 strain of Epstein-Barr virus has been determined. The sequence has been analysed for possible protein coding regions and transcriptional control sites. At least eight large open reading frames were found. Several RNA polymerase II promoters have been identified in the BamHI-B fragments. RNAs transcribed from these promoters are substantially induced by treatment of B95-8 cells with 12-O-tetradecanoylphorbol-13-acetate. Phosphonoacetic acid reversed the stimulatory effect of 12-O-tetradecanoylphorbol-13-acetate on the transcription of these RNAs indicating that they are late RNAs.

Base Sequence↗
PubMed1983

DNA sequence analysis of the EcoRI Dhet fragment of B95-8 Epstein-Barr virus containing the terminal repeat sequences.

An analysis of the approximately 12,440 base-pair sequence of the EcoRI Dhet fragment isolated from the circular episomal form of the B95-8 strain of Epstein-Barr virus is presented. This fragment contains the covalently joined ends of the intracellular episomal form of the molecule. In the viral capsid the DNA is linear and the joining is mediated via the terminal repeated DNA. Four copies of tandem repeated DNA were present in this clone, three with a repeat size of 538 and one of 523. The positions of a number of possible protein coding regions and transcription signals are discussed. In particular a possible spliced coding region for an approximately 45,000 Mr protein expressed in latently infected transformed cells is proposed. The predicted protein sequence contains hydrophobic regions separated by charged amino acids reminiscent of a membrane protein.

Animals↗
PubMed1981

Sequence and organization of the human mitochondrial genome.

The complete sequence of the 16,569-base pair human mitochondrial genome is presented. The genes for the 12S and 16S rRNAs, 22 tRNAs, cytochrome c oxidase subunits I, II and III, ATPase subunit 6, cytochrome b and eight other predicted protein coding genes have been located. The sequence shows extreme economy in that the genes have none or only a few noncoding bases between them, and in many cases the termination codons are not coded in the DNA but are created post-transcriptionally by polyadenylation of the mRNAs.

Base Sequence↗
PubMed1980

A mammalian mitochondrial serine transfer RNA lacking the "dihydrouridine" loop and stem.

A unique transfer RNA has been identified in human and bovine mitochondria that lacks the "dihydrouridine" loop and stem structure. This tRNA is mitochondrially coded as shown by DNA sequence analysis of the human and bovine mitochondrial DNA. Sequence analysis of the RNA shows that it is post-transcriptionally modified by the addition of CCA at the 3' terminus and that at least one base is modified. As predicted by its anticodon (GCU, corresponding to the serine codons AGU/C) this tRNA can be aminoacylated with serine when purified mitochondria are incubated in a medium containing 3H-serine.

Animals↗
PubMed1980

Different pattern of codon recognition by mammalian mitochondrial tRNAs.

Analysis of an almost complete mammalian mitochondrial DNA sequence has identified 23 possible tRNA genes and we speculate here that these are sufficient to translate all the codons of the mitochondrial genetic code. This number is much smaller than the minimum of 31 required by the wobble hypothesis. For each of the eight genetic code boxes with four codons for one amino acid we find a single specific tRNA gene with T in the first (wobble) position of the anticodon. We suggest that these tRNAs with U in the wobble position can recognize all four codons in these genetic code boxes either by a "two out of three" base interaction or by U.N wobble.

Animals↗
PubMed1979

A different genetic code in human mitochondria.

Comparison of the human mitochrondial DNA sequence of the cytochrome oxidase subunit II gene and the sequence of the corresponding beef heart protein shows that UGA is used as a tryptophan codon and not as a termination codon and suggests that AUA may be a methionine and not an isoleucine codon. The cytochrome oxidase II gene is contiguous at its 5' end with a tRNAAsp gene and there are only 25 bases at its 3' end before a tRNALys gene. These tRNA'S are different from all other known tRNA sequences.

Aspartic Acid↗
PubMed1978

Nucleotide sequence of bacteriophage G4 DNA.

The 5,577 nucleotide long sequence of bacteriophage G4 DNA has been determined using the 'plus and minus' and chain termination methods of DNA sequencing. This sequence has been compared with that of the closely related bacteriophage phiX174 (refs 1, 55). In the coding regions there is an average of 33.1% nucleotide sequence differences between the two genomes, but the distribution of these changes is not random and the sequence of some genes is more conserved than others. There is less sequence similarity between the untranslated intergenic regions of G4 and phiX174, but despite this the sequences of the J/F, F/G and H/A untranslated spaces in both genomes have similar sized hairpin loops, which may be related to their function.

Bacteriophages↗