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Diversidad de antígenos en la bacteria B. hermsii a través de mutaciones "somáticas" en genes vmp reorganizados
1Department of Microbiology, University of Texas Health Science Center, San Antonio 78284-7758.
Cell
|September 9, 1994
Resumen
Borrelia hermsii evita las respuestas inmunes a través de la variación antigénica. Los reordenamientos genéticos y las mutaciones crean diversas proteínas VMP, lo que permite a la bacteria persistir durante las infecciones.
Área de la Ciencia:
- Microbiología Microbiología.
- Inmunología Inmunología.
- Genética La genética.
Sus antecedentes:
- Borrelia hermsii emplea variación antigénica multifásica para evadir las respuestas inmunes del huésped.
- Esta variación está mediada principalmente por reorganizaciones de los genes VMP (Vira-Mating-Protein), ubicados en plásmidos.
Objetivo del estudio:
- Para aclarar los mecanismos precisos de la reorganización de genes VMP y la mutación que impulsa la variación antigénica en B. hermsii.
- Investigar el papel de la conversión génica en la generación de diversidad de VMP.
Principales métodos:
- Análisis de las reorganizaciones interplasmídicas e intraplasmídicas de los genes vmp.
- Secuenciación de genes vmp silenciosos y expresados para identificar mutaciones.
- Análisis comparativo de secuencias genéticas con pseudogenes vmp.
Principales resultados:
- La activación de genes vmp silenciosos a través de deleciones intraplasmídicas, pero no la recombinación interplasmídica, precedió a la adquisición de nuevas mutaciones.
- Estas mutaciones aparecieron en el extremo 5' del gen reorganizado y no estaban presentes en el gen silencioso original.
- La prevalencia de alelos mutantes aumentó durante la infección, y las diferencias de secuencia sugirieron la conversión génica de los pseudogenes vmp.
Conclusiones:
- B. hermsii utiliza un mecanismo que implica deleciones intramoleculares seguidas de una conversión génica para generar diversidad de VMP.
- Esta estrategia permite una rápida adaptación y persistencia dentro del entorno inmune del huésped.
- El mecanismo de generación de diversidad de la bacteria es paralelo a las estrategias inmunológicas del huésped para la eliminación de patógenos.
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