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A A Travers

Publications and source records attributed to A A Travers.

77 records · Page 5Linked to original sources
PubMedDate not supplied

Association of an S1 nuclease-sensitive structure with short direct repeats 5' of Drosophila heat shock genes.

The potential for a DNA molecule to assume different tertiary structures has been suggested as a possible determinant of transcriptional regulation in eukaryotes. Such forms include cruciforms transitions from B to Z DNA in the same molecule and short unpaired stretches of DNA in an alternating copolymer. All such structures contain regions which are preferentially sensitive to S1 nuclease. We report here an additional class of S1 nuclease sensitive sites associated with short direct repeats of DNA found in the 5' flanking regions of certain Drosophila melanogaster heat shock genes.

Chromosome Mapping↗
PubMedDate not supplied

Requirement for an upstream element for optimal transcription of a bacterial tRNA gene.

Bacterial promoters are the sites at the 5' end of each gene that bind RNA polymerase and direct the initiation of transcription. The functional elements of Escherichia coli promoters are two highly conserved sequences, each about six nucleotides long, usually centred at sites -10 and -35, +1 being the initiating nucleotide. We have been interested in the structure of promoters of genes that are subject to stringent control, that is whose expression is reduced in conditions of amino acid shortage, such as rRNA and tRNA genes. We have therefore mapped the sequences involved in promoting in vivo transcription of a bacterial tRNATyr (tyrT) gene by fusing the tyrT promoter region to a galactokinase (galK) gene, and using in vivo expression of galactokinase activity to measure promoter strength. We show here that efficient expression from the tyrT promoter requires specific sequences upstream of the canonical promoter elements, and we suggest that these sequences constitute an extended promoter structure.

Base Sequence↗