snRNP: Rich Nuclear Bodies inHyacinthus orientalisL. Microspores and Developing Pollen Cells

摘要

The aim of the present work was the characterization of nuclear bodies in the microspore and developing pollen cells ofHyacinthus orientalisL.. The combination of Ag-NOR, immunofluorescence and immunogold techniques was used in this study. The obtained results showed the presence of highly agyrophylic extranucleolar bodies in microspore and developing pollen cells, which were finally identifiedas Cajal bodies. In all cases, a strong accumulation of snRNP-indicating molecules including TMG cap, Smproteins and U2 snRNA, was observed in the examined nuclear bodies. In contrast to their number thesize of the identified structures did not change significantly during pollen development. In the microsporeand the vegetative cell of pollen grains CBs were more numerous than in the generative cell. At laterstages of pollen development, a drastic decrease in CB number was observed and, just before anthesis, acomplete lack of these structures was indicated in both pollen nuclei. On the basis of these results, as well as our previous studies, we postulate a strong relationship between Cajal body numbers and the levels ofRNA synthesis and splicing machinery elements in microspore and developing pollen cells.