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La secuencia de ADN del erizo de mar (S. purpuratus) H2A, H2B y H3 codificación de histonas y regiones espaciadoras

I Sures, J Lowry, L H Kedes

|November 1, 1978

Resumen

Se secuenciaron genes de histona de erizo de mar activos en el desarrollo temprano. La presencia de metionina en H2A sugiere que estos segmentos de ADN clonados son cruciales para la expresión génica embrionaria.

Área de la Ciencia:

Biología Molecular Biología Molecular
Biología del desarrollo Biología del desarrollo.
Genética La genética.

Sus antecedentes:

Las histonas son cruciales para el empaquetado del ADN en los eucariotas.
Los genes de la histona del erizo de mar están organizados en unidades de repetición.
Las variantes específicas de histona se expresan durante la embriogénesis temprana.

Objetivo del estudio:

Para determinar la secuencia de ADN de las unidades de repetición del gen histona clonado del erizo de mar S. purpuratus.
Para analizar las regiones codificantes y espaciadoras de estos genes histónicos.
Para inferir la actividad del desarrollo de los genes de histona clonados.

Principales métodos:

Secuenciación de ADN de segmentos de genes de histona de erizo de mar clonados.
Análisis de las regiones de codificación para la composición de aminoácidos.
Comparación de secuencias de ADN con secuencias conocidas de proteínas histónicas.

Principales resultados:

Secuenciado dos segmentos clonados que contienen genes H2B, H3 y H2A con espaciadores flanqueantes.
Se identificó un residuo de metionina en la proteína H2A, lo que indica una actividad temprana en el desarrollo.
Se observó una selección sesgada del codón y co-linealidad con las secuencias de proteínas, faltando inserciones de región codificante.
Se encontraron regiones espaciadoras ricas en AT con grupos de GC dispersos y secuencias homólogas conservadas en regiones reguladoras.

Conclusiones:

Las secuencias de ADN clonadas representan genes histónicos activos durante la embriogénesis temprana del erizo de mar.
Las secuencias conservadas en las regiones espaciadoras pueden desempeñar un papel en la transcripción génica o la traducción del ARNm.
La unidad de repetición del gen histona contiene características estructurales únicas, incluida una repetición específica en el espaciador H2A-H1.

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