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Se encuentran secuencias espaciadoras no transcritas de ADNr de ratón flanqueando los genes de inmunoglobulina CH y
Cell
|November 1, 1980
Resumen
Se encuentran secuencias de espaciador no transcrito (rDNA NTS) de ADN ribosómico de ratón dispersas por todo el genoma. Estas secuencias de NTS de rDNA también se identificaron flanqueando genes de cadena pesada de inmunoglobulinas, incluso cerca de la secuencia de codificación de la cadena pesada mu.
Área de la Ciencia:
- La genómica es la genómica.
- Biología Molecular Biología Molecular
- Inmunogenética La inmunogenética.
Sus antecedentes:
- La estructura y la distribución genómica de las regiones de espaciador no transcrito (rDNA NTS) del ADN ribosomal del ratón no se comprenden completamente.
- Estudios anteriores se han centrado en la naturaleza repetitiva del ADNr, pero las secuencias homólogas dispersas no se han investigado ampliamente.
Objetivo del estudio:
- Para investigar la distribución genómica de las secuencias NTS de ADNr de ratón.
- Para determinar si las secuencias de rDNA NTS están asociadas con familias genéticas específicas, como los genes de las inmunoglobulinas.
Principales métodos:
- Cribado de una biblioteca de genes de ratón BALB/c utilizando un fragmento de Eco RI-Sal I de 6 kb clonado de ratón rDNA NTS.
- Experimentos de hibridación in situ para localizar secuencias homólogas.
- Caracterización de clones de fagos recombinantes seleccionados.
- Análisis de las secuencias de flanqueo de los genes de cadena pesada (CH) de las inmunoglobulinas (mu, alfa, gamma 2b).
Principales resultados:
- Una porción significativa (25%) de los fagos recombinantes se hibridaron con la sonda rDNA NTS, lo que indica una amplia difusión de secuencias homólogas.
- La hibridación in situ y la caracterización de clones confirmaron que las secuencias homólogas al rDNA NTS están dispersas por todo el genoma del ratón.
- Se encontraron secuencias homólogas de rDNA NTS que flanqueaban los genes de inmunoglobulina CH mu, alfa y gamma 2b de ratón.
- Una región homóloga NTS específica de rDNA se localizó 3' a la secuencia codificante mu, dentro de una secuencia intermedia identificada.
Conclusiones:
- Las secuencias NTS del ADNr del ratón no se limitan al locus del ADN ribosomal, sino que están dispersas por todo el genoma.
- Estas secuencias dispersas de rDNA NTS muestran una asociación con los loci genéticos de la inmunoglobulina de cadena pesada.
- La localización cerca del gen de la cadena pesada mu sugiere un papel potencial en la regulación o evolución del gen de la inmunoglobulina.
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