Electron microscopic data for the presence of post-meiotic gene expression in isolated ram sperm chromatin

A whole mount electron microscopic technique facilitated a direct visualization of transcripts in ram spermatozoa in run-on experiments. The localization of transcripts in sperm chromatin by spreading enabled identification of regions where transcription complexes, presumably pre-mRNA species, were seen related to chromatin. In another series of experiments the localization of polymerase II was demonstrated using a specific antibody against the conservative tail domain of the polymerase II molecule, followed by protein A-gold visualization on spread chromatin and on thin sections from mature spermatozoa. Incorporation of bio-UTP in transcripts was visualized by streptavidin-gold on spreading and on thin sections. The data suggest that transcription occurs at the periphery of the mature spermatozoa.