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RNA polymerase I can mediate expression of CAT and neo protein‐coding genes in Trypanosoma brucei.
Author(s) -
Rudenko G.,
Chung H.M.,
Pham V.P.,
Van der Ploeg L.H.
Publication year - 1991
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1991.tb04903.x
Subject(s) - columbia university , biology , library science , genetics , trypanosoma brucei , gene , sociology , media studies , computer science
We show that the ribosomal RNA (rRNA) promoter can efficiently direct expression of protein‐coding genes in the parasitic protozoan Trypanosoma brucei. The rRNA promoter was characterized by: (i) point mutations at the rRNA transcription initiation site which completely abolished its promoter function in transient CAT transformation assays; (ii) the alpha‐amanitin resistance of transcription of rRNA promoter‐neomycin phosphotransferase (neo) genes in stably transformed trypanosomes; and (iii) the nucleolar location of neo RNA, synthesized under the control of the rRNA promoter. The rRNA promoter‐derived CAT mRNA required a 3′ splice acceptor site and the neo mRNA was trans‐spliced and polyadenylated. In situ hybridization revealed neo RNA at the nucleolus in stably transformed trypanosomes in which rRNA promoter‐neo constructs were integrated either at a rRNA locus or at a locus for the procyclic acidic repetitive protein (PARP) coding genes. We postulate that trans‐splicing, by uncoupling the requirement for transcription of protein‐coding genes by RNA polymerase II, allows RNA polymerase I mediated protein‐coding gene transcription, presumably because a 5′ cap can be transferred to the pre‐mRNA by trans‐splicing.