Deletion of the 3' half of the yeast tRNA-Leu3 gene does not abolish promotor function in vitro.

The promotor function of the 3' and 5' half tRNA sequences in the yeast tRNA-Leu3 gene has been studied by in vitro transcription in Xenopus laevis germinal vesicle (GV) extracts. Truncation of the DNA template within the tRNA intervening sequence by Hpa I abolishes transcription. However, separation of the tRNA gene halves by insertion of a 300 bp DNA fragment at the Hpa I site does not affect the promoter efficiency. Further, the complete sequence of the 3' half of the tRNA is not necessary for promoter function, because removal of the 3' half of the gene by cleavage with Pvu II, within the DNA inserted at the Hpa I site, does not inhibit transcription.