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Retronphage phi R73: un fago de E. coli que contiene un retroelemento y se integra en un gen de tRNA
S Inouye1, M G Sunshine, E W Six
1Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey at Rutgers, Piscataway 08854.
Science (New York, N.Y.)
|May 17, 1991
Resumen
Los investigadores descubrieron un nuevo fago retrónico, phi R73, en Escherichia coli. Este fago retrónico facilita la transferencia intercelular de retroelementos (retrones) y ADN multicopia de una sola cadena (ADNm), arrojando luz sobre los orígenes de los retrones.
Área de la Ciencia:
- Microbiología Microbiología.
- Biología Molecular Biología Molecular
- Genética La genética.
Sus antecedentes:
- Escherichia coli puede albergar retroelementos llamados retrones, que codifican para la transcriptasa inversa y el ADN multicopia de una sola hebra (msDNA).
- El origen evolutivo y los mecanismos de transferencia de estos elementos retrónicos siguen siendo en gran medida desconocidos.
- Los retrones están asociados con moléculas de ADN ramificado, multicopia, de una sola hebra (msDNA) vinculadas al ARN.
Objetivo del estudio:
- Para investigar el origen y los mecanismos de transferencia de retroelementos (retrones) en Escherichia coli.
- Para caracterizar una prófaga críptica de tipo P4 recientemente identificada que contiene un elemento retrónico.
Principales métodos:
- Análisis genómico de una cepa clínica de Escherichia coli para identificar elementos propágicos.
- La escisión mediada por el bacteriófago P2 y el envasado del prófago identificado.
- Caracterización del genoma del profago y su sitio de integración en un nuevo huésped.
Principales resultados:
- Se identificó un prófago críptico similar a P4, llamado phi R73, en una cepa de E. coli, que contiene el elemento retrónico Ec73.
- El genoma del prófago phi R73 (12,7 kbp) está flanqueado por repeticiones directas del gen selC.
- El bacteriófago P2 facilitó la escisión y el envasado de phi R73, lo que permitió su transferencia intercelular y la lisogenización de nuevos huéspedes a través del gen selC.
Conclusiones:
- El elemento retrónico Ec73 puede ser transferido intercelularmente a través de un retrónfago dependiente del ayudante, phi R73.
- Este descubrimiento proporciona información sobre el origen y la naturaleza móvil de los elementos retrónicos.
- Retronphage phi R73 exhibe características similares a las de P4 en su estructura de viriones y en su crecimiento lítico.
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