This study has analysed by immunocytochemistry the expression pattern of histone H1° after the osmotically induced activation of transcription in supraoptic nucleus neurons of the rat. In control rats, histone H1° was constitutively expressed in neuronal and glial cell nuclei of supraoptic nucleus. After chronic neuronal stimulation by intermittent salt-loading, the majority of neuronal cell nuclei exhibited a marked reduction of immunostaining, which was confirmed by densitometric analysis of immunoreactivity. This effect was reversible, since optical density values returned to control levels when the stimulation of supraoptic neurons was suppressed by rehydration. Ultrastructural immunocytochemistry of histone H1° showed that immuno-gold particles specifically decorated chromatin fibers, with the highest accumulation of particles being on the condensed inactive chromatin. These results indicate that transcriptional activation in supraoptic neurons is accompanied by a depletion of the chromatin-associated histone H1°, and also suggest that this transcription-dependent expression of histone H1° may be involved in regulating chromatin condensation and gene expression in mature neurons that constitutively express this protein. © 1995.
|Journal||Molecular Brain Research|
|Publication status||Published - 1 Jan 1995|
- Cell nucleus
- Histone H1°
- Supraoptic nucleus