Remodeling of sperm chromatin after fertilization involves nucleosomes formed by sperm histones H2A and H2B and two CS histone variants

M. Isabel Oliver, Carolina Concha, Soraya Gutiérrez, Alejandra Bustos, Martín Montecino, Marcia Puchi, María Imschenetzky

Resultado de la investigación: Contribución a una revistaArtículo

12 Citas (Scopus)

Resumen

The composition of nucleosomes at an intermediate stage of male pronucleus formation was determined in sea urchins. Nucleosomes were isolated from zygotes harvested 10 min post-insemination, whole nucleoprotein particles were obtained from nucleus by nuclease digestion, and nucleosomes were subsequently purified by a sucrose gradient fractionation. The nucleosomes derived from male pronucleus were separated from those derived from female pronucleus by immunoadsorption to antibodies against sperm specific histones (anti-SpH) covalently bound to Sepharose 4B (anti-SpH-Sepharose). The immunoadsorbed nucleosomes were eluted, and the histones were analyzed by Western blots. Sperm histones (SpH) or alternatively, the histones from unfertilized eggs (CS histone variants), were identified with antibodies directed against each set of histones. It was found that these nucleosomes are organized by a core formed by sperm histones H2A and H2B combined with two major CS histone variants. Such a hybrid histone core interacts with DNA fragments of approximately 100 bp. It was also found that these atypical nucleosome cores are subsequently organized in a chromatin fiber that exhibits periodic nuclease hypersensitive sites determined by DNA fragments of 500 bp of DNA. It was found that these nucleoprotein particles were organized primarily by the hybrid nucleosomes described above. We postulate that this unique chromatin organization defines an intermediate stage of male chromatin remodeling after fertilization.

Idioma originalInglés
Páginas (desde-hasta)851-859
Número de páginas9
PublicaciónJournal of Cellular Biochemistry
Volumen85
N.º4
DOI
EstadoPublicada - 2002

Áreas temáticas de ASJC Scopus

  • Bioquímica
  • Biología celular
  • Biología molecular

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