Organization of centromeres in the decondensed nuclei of mature human sperm.

The localization of centromeres in mature human sperm was shown by immunofluorescent labeling and nonisotopic in situ hybridization. In the decondensed nucleus structural elements (dimers, tetramers, linear arrays and V shape structures) formed by individual centromeres of nonhomologous chromosomes were observed. They organize the compact chromocenter, which was shown for nuclei decondensed to a low extent. The chromocenter is buried inside the nucleus; in contrast, telomeric regions of chromosomes were tentatively localized on the periphery. Thus, a gross architecture, which can influence selective unpackaging of the paternal genome upon fertilization, exists in human sperm.