In vivo effects of Trichostatin A - A histone deacetylase inhibitor - On chromatin remodeling during Triturus cristatus spermatogenesis.

A major challenge in developmental biology field is to decipher the molecular mechanisms involved in cellular differentiation and to understand the processes that control and regulate genes expression. The study of nuclear molecular architecture during gametogenesis represents one approach toward deciphering the molecular organization and function of the eukaryotic chromatin. As spermatogenesis progresses, there is a widespread reorganization of the haploid genome followed by extensive DNA compaction. It is becoming increasingly evident that the dynamic composition of chromatin plays an important role in the activities of enzymes and in the processes that act upon it. As the information in the existing literature regarding the epigenetic modifications occurring in the advanced stages of spermatogenesis of crested newt is still scarce, we have investigated the effect of a Histone Deacetylase (HDAC) inhibitor, Trichostatin A (TSA), at the cytological level (by transmission electron microscopy - TEM, immunohistochemistry technique, fluorescence microscopy) and at the molecular level (AUT-PAGE and ChIP assay) on Triturus cristatus spermatogenesis. Our results have revealed an important role for regulation of histone deacetylase activity in controlling histone hyperacetylation and the replacement with sperm nuclear basic proteins during spermiogenesis.