Coiled bodies in nuclei from plant cells evolving from dormancy to proliferation

To characterise the coiled bodies in meristematic nuclei of Saccharum officinarum, immunofluorescence labelling with antibodies against components of the splicing (U2B' and Sm core protein B) and pre-rRNA processing (fibrillarin) complexes was used in cells from the dormant root primordia and from roots at different times after activation to the steady state of proliferation. The number, size and distribution of coiled bodies varied in the meristematic tissue depending on cell activity. While G0 cells in the dry primordia and proliferating cells showed a similar number of coiled bodies attached to their nucleoli, the number of nucleoplasmic coiled bodies greatly increased after the primordia were stimulated to proliferate. Their number remained steady from the time the meristematic population reached the steady state of proliferation, as estimated by flow cytometry. Fractionation studies demonstrated that coiled bodies are a part of the underlying nuclear matrix. Comparison of immunocytochemical and cytochemical data from confocal and electron microscopical studies demonstrated that the nucleolar and nucleoplasmic coiled bodies detected by confocal microscopy shared many features, suggesting that they form a family of closely related structures.