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Los genes y el ARNm que codifican las cadenas pesadas del esqueleto embrionario de pollo, la miosina
Cell
|October 1, 1977
Resumen
Los investigadores aislaron polisomas del músculo de pollo para estudiar la síntesis de la miosina de cadena pesada (MHC). Descubrieron que el ARNm MHC dirige la producción de dos cadenas MHC distintas, con una mínima repetición de genes en el genoma.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Fisiología Muscular Fisiología Muscular
- Biología del desarrollo Biología del desarrollo.
Sus antecedentes:
- La miosina de cadena pesada (MHC) del músculo esquelético es crucial para la contracción muscular.
- Comprender la expresión génica del MHC es clave para el desarrollo y la función muscular.
Objetivo del estudio:
- Para aislar y caracterizar el mRNA de cadena pesada de miosina (MHC mRNA) del músculo esquelético embrionario de pollo.
- Para investigar la síntesis y las propiedades de las cadenas de polipéptidos MHC producidas in vitro.
- Para determinar el número de copia del gen para MHC en el genoma del pollo.
Principales métodos:
- Aislamiento de polisomas del músculo esquelético de la pierna embrionaria del pollo.
- Purificación del mRNA MHC y la traducción libre de células utilizando un sistema de germen de trigo.
- Análisis de cadenas polipeptídicas sintetizadas utilizando la determinación del peso molecular y el enfoque isoeléctrico.
- Análisis cinético de la hibridación del ADN complementario (ADNc) con el ARNm MHC y el ADN genómico.
Principales resultados:
- Los polisomas sintetizaron una cadena polipeptídica idéntica en peso molecular a la cadena pesada de miosina.
- La traducción in vitro del ARNm purificado de MHC produjo un polipéptido de 200.000 daltones, con >90% que exhiben propiedades similares a las del MHC.
- El enfoque isoeléctrico reveló dos cadenas iguales en el MHC sintetizado in vitro, reflejando el MHC embrionario nativo.
- La cinética de la hibridación indicó dos secuencias distintas de ARNm MHC y sugirió una baja repetición de genes MHC en el genoma.
Conclusiones:
- El ARNm del músculo esquelético embrionario del pollo MHC dirige la síntesis de una cadena polipeptídica que se asemeja mucho al MHC nativo.
- El MHC sintetizado comprende dos cadenas polipeptídicas distintas, lo que sugiere una regulación compleja.
- Es probable que los genes de cadena pesada de miosina estén presentes en bajos números de copias dentro del genoma del pollo.
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