Methodical aspects of 3-D reconstruction of chromatin architecture in mouse trophoblast giant nuclei.

Precise 3-D reconstruction of the spatial organization of murine trophoblast giant-cell chromatin is a prerequisite for detailed investigations on the fine structural changes in chromatin-fibre organization during the trophoblast endomitotic cell cycle. It appears very likely that sequential fine structural changes in the chromatin arrangement are concomitant with the changes in the gene expression pattern of these cells during the early phase of murine gestation. The complex intra-nuclear chromatin organization of mouse trophoblast giant nuclei was investigated in permanent tissue preparations which had been stained with a DNA-specific dye. The spatial chromatin arrangement was examined in fluorescence with a confocal scanning laser microscope. Serial optical sections were recorded and subjected to a computer-based 3-D reconstruction method which is suitable even for very complex biological structures.