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The Trypanosoma brucei spliced leader RNA and rRNA gene promoters have interchangeable TbSNAP50-binding elements
被引:35
作者:
Schimanski, B
Laufer, G
Gontcharova, L
Günzl, A
机构:
[1] Univ Connecticut, Ctr Hlth, Ctr Microbial Pathogenesis, Farmington, CT 06030 USA
[2] Univ Tubingen, Inst Zool, Abt Zellbiol, D-72076 Tubingen, Germany
关键词:
D O I:
10.1093/nar/gkh231
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
In the protist parasite Trypanosoma brucei, the small nuclear spliced leader (SL) RNA and the large rRNAs are key molecules for mRNA maturation and protein synthesis, respectively. The SL RNA gene (SLRNA) promoter recruits RNA polymerase II and consists of a bipartite upstream sequence element (USE) and an element close to the transcription initiation site. Here, we analyzed the distal part of the ribosomal (RRNA) promoter and identified two sequence blocks which, in reverse orientation, closely resemble the SLRNA USE by both sequence and spacing. A detailed mutational analysis revealed that the ribosomal (r)USE is essential for efficient RRNA transcription in vivo and that it functions in an orientation-dependent manner. Moreover, we showed that USE and rUSE are functionally interchangeable and that rUSE stably interacted with an essential factor of SLRNA transcription. Finally, we demonstrated that the T.brucei homolog of the recently characterized transcription factor p57 of the related organism Leptomonas seymouri specifically bound to USE and rUSE. Since p57 and its T.brucei counterpart are homologous to SNAP50, a component of the human small nuclear RNA gene activation protein complex (SNAPc), both SLRNA and RRNA transcription in T.brucei may depend on a SNAPc-like transcription factor.
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页码:700 / 709
页数:10
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