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https://www.arca.fiocruz.br/handle/icict/57346
DISSECTING TRYPANOSOMA BRUCEI RRP44 FUNCTION IN THE MATURATION OF SEGMENTED RIBOSOMAL RNA USING A REGULATED GENETIC COMPLEMENTATION SYSTEM
ARN Lider Empalmado
Complementación Genética
Processamento de RNA
RNA Líder para Processamento
Complementação Genética
Author
Affilliation
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil. / Universidade Federal do Paraná. Programa de Pós-Graduação em Bioquímica. Curitiba, PR, Brasil.
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil. / Universidade Federal do Paraná. Programa de Pós-Graduação em Bioquímica. Curitiba, PR, Brasil.
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil. / Universidade Federal do Paraná. Programa de Pós-Graduação em Bioquímica. Curitiba, PR, Brasil.
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil. / Universidade Federal do Paraná. Programa de Pós-Graduação em Bioquímica. Curitiba, PR, Brasil.
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.
Abstract
Trypanosoma brucei belongs to a group of protozoans presenting fragmented large subunit rRNA. Its LSU rRNA equivalent to the 25S/28S rRNA of other eukaryotes is split into six fragments, requiring additional processing for removal of the extra spacer sequences. We have used a genetic complementation strategy to further investigate the T. brucei RRP44 nuclease in pre-rRNA maturation. TbRRP44 contains both a PIN and a RNB domain whose homologues are found in association with the exosome complex.We found that the exonucleolytic activity of the RNB domain as well as the physical presence of the PIN domain are essential for TbRRP44 function, while a catalytic site mutation in the PIN domain has no detectable effect on cell growth. A new endonucleolytic cleavage site in ITS1 was identified. In addition to the 5.8S rRNA 3 -end maturation, TbRRP44 is required for degradation of the excised 5 -ETS and for removal of part of ITS1 during maturation of the 18S rRNA 3 -end. TbRRP44 deficiency leads to accumulation of many LSU intermediate precursors, most of them not detected in control cells. TbRRP44 is also required for U3 snoRNA and spliced leader processing, indicating that TbRRP44 may have a wide role in RNA processing in T. brucei.
Keywords in Portuguese
T. brucei RRP44Keywords in Spanish
Procesamiento Postranscripcional del ARNARN Lider Empalmado
Complementación Genética
DeCS
Trypanosoma brucei bruceiProcessamento de RNA
RNA Líder para Processamento
Complementação Genética
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