α-Amanitin-insensitive transcription of variant surface glycoprotein genes provides further evidence for discontinuous transcription in trypanosomes
Year: 1984
Type: article
Abstract: Many, if not all, mRNAs in T.brucei start with the same sequence of 35 nucleotides, separately encoded in clustered so-called mini-exon repeats. From these mini-exon repeats a 141-nt precursor RNA with the 35-nt sequence at its 5' end is transcribed. Indirect evidence suggests that this RNA is linked in a second step to pre-mRNA transcripts. We have studied the sensitivity of RNA synthesis to alpha-amanitin in isolated trypanosome nuclei. Transcription of several protein coding genes is almost completely inhibited by a concentration of 5 micrograms alpha-amanitin per ml, whereas strong inhibition of mini-exon transcription is achieved with 200 micrograms alpha-amanitin per ml. In contrast, transcription of genes for variant surface glycoproteins (VSGs) is not inhibited by 1000 micrograms alpha-amanitin per ml, as is transcription of the genes for the major rRNAs. Since the mature VSG mRNAs start with the 35-nt sequence, our results provide additional evidence that the 35-nt sequence and the main part of VSG mRNA are produced from independent transcription units, these are transcribed by (partly) different RNA polymerases.
Source: Nucleic Acids Research
Authors: Jan M. Kooter, Piet Borst
Institution: The Netherlands Cancer Institute
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W2031620624