[Immunofluorescent detection of nuclear actin in early mouse embryos]

In this work, preimplantation mouse embryos were used as a model to study the distribution of nuclear actin in a comparative aspect. To reveal actin, different polyclonal antibodies raised against the C-terminal domains of actin were applied. An antibody raised against the C-terminal marks nuclear actin more intensively as compared to the cytoplasm, especially in areas of condensed chromatin. The fluorescence of the nuclei was less apparent when an antibody against N-terminus is applied. This antibody revealed actin associated with low condensed chromatin. In 2-cell but not in elder embryos, some Cajal bodies were also stained with this antibody. However, the pattern of actin association with transcriptions sites does not depend on the type of anti-actin antibodies used in this study. We suggest that the distinctions of staining patterns revealed using different anti-actin antibodies may be explained by different capacity of the antibodies for staining, but not by their selective detection of different functional forms of nuclear actin in mouse embryos.