Mutational analysis of the coordinate expression of the yeast tRNAArg-tRNAAsp gene tandem.

摘要: tRNA genes occur in the yeast genome as highly dispersed and independent transcriptional units. The 5'-tRNAArg-tRNAAsp-3' gene tandem, separated by a 10-base-pair spacer sequence, thus represents rare case of tight clustering. Previous vitro studies did not reveal any primary transcript from tRNAAsp gene, but rather dimeric precursor containing both sequences plus spacer, which undergoes series maturation steps. This seems anomalous since contains necessary for its own transcription. We found that site-directed mutation conserved C at position 56 to G tRNAArg suppresses all transcription does activate gene. Precise deletion entire gives similar result. Rescue is effected either precise or this with concomitant introduction an artificial RNA polymerase III start site spacer. ineffective if present upstream.