Transfer RNA genes require "positive" 5'-flanking sequences to direct efficient transcription. In order to delimit the modulatory sequences present in the 5'-flank of a Drosophila tRNA Val₄ gene, an extensive series of deletion mutants was constructed and end-points determined by dideoxy sequencing. The mutants were transcribed in vitro in a Drosophila Schneider II cell-free extract.
Twenty nucleotides of the 5'-flank immediately adjacent to the mature tRNA coding sequence were required for transcription.
Negative modulatory sequences were contained between positions -20 to -30 and -45 to -70 relative to the mature coding sequence. The -45 to -70 sequence shares homology with inhibitory sequences previously described in the 5'-flank of tRNA genes, except that this sequence was significantly larger in length. Sequences contained between
positions -38 and -45 act as positive modulatory sequences which enhance the level of transcription. In addition, a Transcription Modulation Element (TME) was identified between nucleotides -33 and -38. The TME was also found in the 5'-flanking sequences of various other tRNA genes and preliminary data suggests that it enhances transcription efficiency through its position relative to the D and T control regions / Medicine, Faculty of / Medical Genetics, Department of / Graduate
| Identifer | oai:union.ndltd.org:UBC/oai:circle.library.ubc.ca:2429/24910 |
| Date | January 1985 |
| Creators | Sajjadi, Fereydoun G. |
| Publisher | University of British Columbia |
| Source Sets | University of British Columbia |
| Language | English |
| Detected Language | English |
| Type | Text, Thesis/Dissertation |
| Rights | For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use. |
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