Intracellular PC-GFP distribution during blastoderm nuclear cycles

The movie presented here is meant as an addendum to our article

Dietzel, S., H. Niemann, B. Brückner, C. Maurange and R. Paro (1999).
The nuclear distribution of Polycomb during Drosophila melanogaster development shown with a GFP fusion protein. Chromosoma , 108(2):83-94. ( Abstract)

If you are not coming from there anyway, you might want to check out the introduction page .


Time sequence of the Polycomb-GFP distribution during blastoderm cycles.

Left: GFP fluorescence, right: simultaneous differential interference contrast (DIC) recording. Image size is 40 µm from top to bottom. Confocal 3D stacks were recorded subsequently with a 5 second break in between. From each stack the same section was extracted for display in this movie. The recording of one stack took 30 seconds; the images are thus 35 seconds apart. The 40 frames span about 23 minutes.

Until nuclear cycle 14 all nuclei in the Drosophila embryo divide synchronously in a syncytium where no  cell membranes are formed between the nuclei. Thus, at this stage the embryo is one multinuclear cell. When the nuclear membrane breaks down during mitosis, the nuclear content thus can leak unrestricted into the embryonic cytoplasm. The sequence starts after entering mitosis between cycles 10 and 11 and ends in interphase of cycle 12. In the movie, it can be observed that at the onset of every mitosis the majority of the PC-GFP signal leaks into the cytoplasm. The bulk of the PC-GFP seems to disappear and then reappear during telophase. (This is due to the sudden distribution of the fluorescent molecules in a much larger volume, thus the signal to noise ratio decrease dramatically.) However a very weak but clearly detectable signal remains associated with the chromosomal area. This area is defined by the GFP signal itself but can also be seen in the DIC image because of its higher optical density.

The nuclei shown here are partly presented in our Chromosoma paper in Figure 3A This movie is also available at the Chromosoma Web site here .

If you can't see the movie above, try opening it in a separate window by clicking here . That also might help if you want to save the movie on your computer



Last Update: 4. September 2000
Back to Polycomb - GFP introductory page
Homepage
This page was made with Netscape Composer and tested with Netscape Navigator and MS Explorer.