When something goes wrong: histone

Presents early embryonic divisions in Drosophila are syncytial. Nuclei undergo mitosis synchronously for the first 14 nuclear cycles, followed by cellularization (Foe and Alberts, 1983). At nuclear cycle 10, nuclei are at the embryo cortex and can be easily visualized. Sliverman's second movie (When Something Goes Wrong - Histone) shows a Drosophila embryo from a line expressing a fusion protein of GFP and histone (Clarkson and Saint, 1999). This fusion protein enables the visualization of DNA and the behavior of chromosomes during two consecutive divisions. Interphase nuclei contain DNA that is not assembled in chromosomes. Chromosome condensation takes place during prophase. In prometaphase, chromosomes attach to division spindles and congress at the cell equator. Once all chromosomes are at the metaphase plate, they segregate and move towards opposite poles in anaphase. In telophase, chromosomes decondense and nuclei reform. If the division went well the cycles start again. However, if anything goes wrong, the chromosomes do not condense and the nuclei sink in the middle of the embryo, a process called nuclear fallout. This is the case with the two nuclei in the middle of the image: each will sink in one of the 2 cycles. Before cellularization 6000 nuclei will formComponente Curricular::Educação Superior::Ciências Biológicas::Biologia Gera