The 5'-flanking sequence of yeast tRNA(Leu3) genes enhances the rate of transcription from stable pre-initiation complexes.
A conserved sequence that enhances transcription is present at or near the 5'-end of genes which code for several abundant yeast tRNAs, one of which is tDNA(Leu3). Mutants with alterations in this region have been compared to the parent tDNA(Leu3) and a yeast tDNA(Ser) that normally lacks the conserved sequence. The apparent KM of the transcription apparatus is insensitive to 5'-flanking sequence variation. Replacement of the normal 5'-flanking sequence does result in 3-18 fold reductions in VMAX and a 7-13 fold loss of transcription in tests with competitor genes. A second template exclusion assay revealed that sequences upstream of the conserved region effect a 2 fold change in the ability of the genes to stably sequester a component(s) of the obligatory pre-initiation complex while positions -22 to +9 have little or no effect.
Raymond
G J
GJ
Department of Molecular Biology, University of Wyoming, Laramie 82071.
Johnson
J D
JD
D001483:Base Sequence; D004271:DNA, Fungal / Q000378:metabolism; D005800:Genes, Fungal; D007700:Kinetics; D011401:Promoter Regions, Genetic; D012345:RNA, Transfer, Amino Acid-Specific / Q000235:genetics*; D012356:RNA, Transfer, Leu / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D013698:Templates, Genetic; D014158:Transcription, Genetic
D004271:DNA, Fungal; D012345:RNA, Transfer, Amino Acid-Specific; D012356:RNA, Transfer, Leu