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Promotor de un gen regulado en el desarrollo en Bacillus subtilis
Cell
|September 1, 1981
Resumen
La esporulación de Bacillus subtilis implica un gen de desarrollo (gen de 0,4 kb) regulado por factores sigma específicos (sigma 37 y sigma 29). Los investigadores identificaron sitios de inicio de doble transcripción y elementos promotores cruciales para este control del desarrollo.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Genética microbiana Genética microbiana.
- Desarrollo bacteriano Desarrollo bacteriano
Sus antecedentes:
- Bacillus subtilis se somete a la esporulación, un complejo proceso de desarrollo.
- Los genes reguladores específicos (loci spo0) controlan el inicio de la esporulación.
- La transcripción génica durante la esporulación está regulada en el desarrollo.
Objetivo del estudio:
- Determinar la secuencia de nucleótidos del promotor para un gen de B. subtilis controlado en el desarrollo (gen de 0,4 kb).
- Para investigar el papel de los factores sigma de la ARN polimerasa en la regulación de la transcripción de este gen.
- Aclarar la estructura del promotor y sus implicaciones para la regulación del desarrollo.
Principales métodos:
- Secuenciación de nucleótidos de la región promotora.
- Ensayos de transcripción in vitro utilizando ARN polimerasa purificada y factores sigma.
- Mapeo de la nucleasa S1, transcripción de escorrentía y primado de dinucleótidos para identificar los sitios de inicio de la transcripción.
- Construcción y análisis de mutaciones de deleción in vitro dentro de la región promotora.
Principales resultados:
- El promotor del gen de 0,4 kb es reconocido por sigma 37 y sigma 29, pero no por sigma 55.
- Se identificaron sitios de inicio de doble transcripción, aproximadamente a 10 bp de distancia, para la transcripción dirigida por sigma 37.
- El análisis de eliminación reveló una región rica en AT esencial para la iniciación de la transcripción aguas abajo y un sitio de inicio aguas arriba.
Conclusiones:
- La estructura promotora del gen de 0,4 kb, con sus sitios de inicio duales y un elemento específico rico en AT, es crítica para la transcripción regulada en el desarrollo en B. subtilis.
- Diferentes formas de ARN polimerasa que contienen sigma 37 exhiben preferencias distintas para los sitios de inicio de la transcripción.
- Estos hallazgos proporcionan información sobre los mecanismos que rigen la expresión génica durante el desarrollo bacteriano y la esporulación.
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