Comparative mutational analysis of wild-type and stretched tRNA3(Leu) gene promoters.
We demonstrate that, when the yeast tRNA(3Leu) gene is stretched so that the distance between the two portions of the intragenic promoter is increased to 365 base pairs, the A and B blocks remain functional. Mutations in the A block, which show a weak phenotype when inserted in the wild type, exert a dramatic effect when inserted into the stretched gene. Experiments with extensively purified transcription factor tau indicate that the tau B-B block interaction is not influenced by A-B distance; only the ability of tau A to interact with A block sequences is affected, possibly because of the additional free-energy cost of forming a large loop of the intervening DNA.
Fabrizio
P
P
Dipartimento di Biologia Cellulare e dello Sviluppo, Università degli Studi La Sapienza, Rome, Italy.
Coppo
A
A
Fruscoloni
P
P
Benedetti
P
P
Di Segni
G
G
Tocchini-Valentini
G P
GP
D001483:Base Sequence; D001665:Binding Sites; D004252:DNA Mutational Analysis; D004271:DNA, Fungal / Q000235:genetics; D004268:DNA-Binding Proteins / Q000502:physiology; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D012345:RNA, Transfer, Amino Acid-Specific / Q000235:genetics*; D012356:RNA, Transfer, Leu / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D012345:RNA, Transfer, Amino Acid-Specific; D012356:RNA, Transfer, Leu; D014157:Transcription Factors