Nuclear bodies in the oocyte nucleus of ground beetles are enriched in snRNPs

Within the oocyte nucleus of many insect species, a variable number of intensely stained spherical bodies occur. These nuclear bodies differ significantly from nucleoli and their precise role in nuclei has not been elucidated yet. I have examined some of the histochemical properties as well as the molecular composition of these structures in a representative of ground (carabid) beetles. I demonstrate, using molecular markers, that the nuclear bodies are composed of small nuclear RNAs and associated proteins, including p80 coilin. Hence, they correspond to Cajal bodies (= coiled bodies) described in somatic cell nuclei as well as oocyte germinal vesicles in plant and animal organisms. It is suggested that Cajal bodies in the carabid germinal vesicle serve as a storage site for splicing factors.