| Autor: |
Saito RM; Department of Microbiology and Immunology, University of California, Los Angeles, CA 90024., Elgort MG, Campbell DA |
| Jazyk: |
angličtina |
| Zdroj: |
The EMBO journal [EMBO J] 1994 Nov 15; Vol. 13 (22), pp. 5460-9. |
| DOI: |
10.1002/j.1460-2075.1994.tb06881.x |
| Abstrakt: |
We demonstrate that the mini-exon genes of Leishmania tarentolae are individually transcribed by an enzyme pharmacologically identified as RNA polymerase II. To study transcription in these ancient eukaryotes, a stable transformation assay using an episomal mini-exon gene was developed. The introduced mini-exon gene, which had been marked with a 40 bp tag, yielded the predicted tagged transcript. An upstream cis-acting element that was essential for transcription of the mini-exon gene was identified by site-directed mutagenesis. Block substitution mutagenesis of the -1 to +9 and +10 to +19 regions of the exon results in 20- to 100-fold decreased levels of the tagged transcript in steady-state RNA. However, since these two mutations resulted in only a 2- to 3-fold decrease in nascent RNA levels, steady-state levels appear to be affected greatest by the stability of the resulting transcript. In contrast, mutation of the -67/-58 region resulted in undetectable levels of both steady-state and nascent RNA from the introduced gene. We conclude, therefore, that this upstream element, which is highly conserved in all Leishmania species, is a component of the mini-exon gene promoter. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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