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Immunobiochemical evidence for the loss of sperm specific histones during male pronucleus formation in monospermic zygotes of sea urchins
Author(s) -
Imschenetzky Maria,
Puchi Marcia,
Pimentel Cecilia,
Bustos Alejandra,
Gonzales Margarita
Publication year - 1991
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240470102
Subject(s) - pronucleus , zygote , sea urchin , sperm , male pronucleus , polyspermy , microbiology and biotechnology , biology , botany , oocyte , embryogenesis , embryo
To obtain information on the remodeling of sperm chromatin during male pronuclei formation, we have followed the sperm specific histones (SpH) that form the nucleosomal core by Western imunoblot analysis with policlonal antibodies directed against the core SpH. The results obtained indicate that the complete set of SpH is absent from zygote chromatin at the beginning of the first S phase. The disappearance of SpH is not coincidental for the five histone classes: SpH4 and SpH3 are lost 5–15 min post insemination (p.i.), SpH2B and SpH2A disappear 20–40 min p.i., and SpH1 is progressively diminished up to 30 min p.i. This order of sperm chromatin remodeling is not affected by the inhibition of protein synthesis by emetine, indicating that the factor(s) responsible for SpH disappearance are present in unfertilized eggs. The lost SpH's are not replaced by newly synthesized CS variants, since the basic proteins synthesized de novo during male pronuclei formation are not incorporated into chromatin remaining in the cytoplasm. These newly synthesized proteins are different from the CS variants as judged by their electrophoretic migration.