Competitive folding of RNA structures at a termination-antitermination site.
RNA
; 23(5): 721-734, 2017 05.
Article
em En
| MEDLINE
| ID: mdl-28235843
ABSTRACT
Antitermination is a regulatory process based on the competitive folding of terminator-antiterminator structures that can form in the leader region of nascent transcripts. In the case of the Bacillus subtilis licS gene involved in ß-glucosides utilization, the binding of the antitermination protein LicT to a short RNA hairpin (RAT) prevents the formation of an overlapping terminator and thereby allows transcription to proceed. Here, we monitored in vitro the competition between termination and antitermination by combining bulk and single-molecule fluorescence-based assays using labeled RNA oligonucleotide constructs of increasing length that mimic the progressive transcription of the terminator invading the antiterminator hairpin. Although high affinity binding is abolished as soon as the antiterminator basal stem is disrupted by the invading terminator, LicT can still bind and promote closing of the partially unfolded RAT hairpin. However, binding no longer occurs once the antiterminator structure has been disrupted by the full-length terminator. Based on these findings, we propose a kinetic competition model for the sequential events taking place at the termination-antitermination site, where LicT needs to capture its RAT target before completion of the terminator to remain tightly bound during RNAP pausing, before finally dissociating irreversibly from the elongated licS transcript.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Fatores de Transcrição
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Proteínas de Ligação a RNA
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Regiões 5' não Traduzidas
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Dobramento de RNA
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Terminação da Transcrição Genética
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
RNA
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
França