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Estructura secundaria de los ARNm alfa- y beta-globina de ratones y conejos: accesibilidad diferencial de los codones

G N Pavlakis, R E Lockard, N Vamvakopoulos

|January 1, 1980

Resumen

La investigación de los ARN mensajeros de globina de ratón y conejo reveló diferencias en la accesibilidad del codón iniciador. El ARNm de la beta-globina es el ARNm beta-globina.

Área de la Ciencia:

Biología Molecular Biología Molecular
Genética La genética.
La bioquímica es la bioquímica.

Sus antecedentes:

Los ARN mensajeros (ARNm) codifican proteínas, y su iniciación de la traducción es un paso regulatorio crítico.
Los ARNm alfa y beta de la globina son esenciales para la síntesis de hemoglobina, con una expresión diferencial observada en varias condiciones.
La estructura secundaria del ARNm puede influir en la eficiencia de la traducción y las tasas de iniciación.

Objetivo del estudio:

Para establecer la secuencia de nucleótidos de los ARN mensajeros alfa y beta-globina de ratón (ARNm).
Para analizar las estructuras secundarias de los ARNm alfa y beta-globina de ratones y conejos.
Investigar la accesibilidad del codón iniciador AUG en los ARNm alfa y beta-globina y su correlación con las tasas de iniciación de la traducción.

Principales métodos:

Secuenciación del extremo 5' de los ARNm alfa y beta-globina de ratón.
Análisis de estructuras secundarias de ARNm utilizando ARNm con etiqueta final 5' 32P como sustratos.
Sondaje enzimático con nucleasas S1 y T1 para identificar regiones de cadena única.

Principales resultados:

El codón iniciador de AUG en el ARNm beta-globina (tanto en ratón como en conejo) es accesible para las nucleasas S1 y T1, lo que indica que se encuentra en una región expuesta.
El codón iniciador AUG en el ARNm alfa-globínico (ambas especies) es inaccesible para estas nucleasas, lo que sugiere que está enterrado o emparejado con bases.
Las tasas de iniciación de la traducción para el ARNm beta-globina son un 30-40% más rápidas que para el ARNm alfa-globina en los lisados de reticulocitos de conejo.

Conclusiones:

La accesibilidad del codón iniciador AUG se correlaciona con la velocidad de inicio de la síntesis de proteínas.
Los codones AUG expuestos en el ARNm beta-globina facilitan una iniciación de traducción más rápida en comparación con el AUG menos accesible en el ARNm alfa-globina.
La estructura secundaria del ARNm juega un papel importante en la regulación de la expresión génica de la globina a nivel de traducción.

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