In vitro studies of meiotic maturation of mouse oocytes have been carried out in the presence of several drugs. The individual steps of nuclear progression, including dissolution of the nuclear (germinal vesicle) membrane, condensation of dictyate chromatin into compact bivalents, formation of the first metaphase spindle, and extrusion of the first polar body, are each susceptible to one or mor...

During cell division, chromatin alternates between a condensed state to facilitate chromosome segregation and a decondensed form when DNA replicates. In most tissues, S phase and mitosis are separated by defined G1 and G2 gap phases, but early embryogenesis involves rapid oscillations between replication and mitosis. Using Caenorhabditis elegans embryos as a model system, we show that chromosom...

Chromosomal transcription involves the concerted action of enormous, multisubunit chromatin remodeling complexes. A recent study, however, suggests a different and surprising viewpoint in which these protein assemblies are quite dynamic and individual subunits play key roles in chromatin remodeling.

Andrew J Wood and Wendy A Bickmore* Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California-Berkeley, Berkeley, CA, USA, Department of Medical and Molecular Genetics, King’s College London, Guy’s Hospital, London, UK and MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK *Correspondence to: W....

Transition nuclear proteins (TPs), the major proteins found in chromatin of condensing spermatids, are believed to be important for histone displacement and chromatin condensation during mammalian spermatogenesis. We generated mice lacking the major TP, TP1, by targeted deletion of the Tnp1 gene in mouse embryonic stem cells. Surprisingly, testis weights and sperm production were normal in the ...

Considering that the final protection of the DNA against major assaults in terms of chromatin condensation is finalized in the epididymis, it is not known how sperm production of reactive oxygen species (ROS) and inflammatory processes can contribute to protamine deficiency that is predetermined in the testes. Therefore, this study aimed at investigating relationships between poor chromatin con...