File:Open, closed and semi-open mitosis.jpg

Original file name: Img073.jpg

Comparison of the various forms of mitosis in different eukaryotes

Student drawn image created by z3331556

This drawing is based on an image found in the article Double duty for nuclear proteins – the price of more open forms of mitosis

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2829850/

This drawing depicts the variant forms of mitosis occurring in higher and lower eukaryotic organisms. (a) S. cerevisiae, is a species of yeast and an example of a low eukaryote which undergoes closed mitosis. Its nuclear envelope (NE), including nuclear pore complexes (NPCs), remains intact throughout cell division and its microtubule organising centre (MTOC) is embedded withing the NE resulting in the nucleoplasmic spindle formation (b) Ustilago maydis, is a fungal pathogen of corn and it undergoes a variant form of "open" mitosis. Its nuclear membranes remain intact but NPCs are dissociated during mitosis. Most importantly its MTOC are removed from the NE and results in cytoplasmic spindle formation (c) Early Drosophila embryos undergo a semi-closed/open mitosis where its NE is partially broken down (with the removal of NPCs) during mitosis. The MTOCs are located in the cytoplasm outside the NE and cytoplasmic spindles form. The remaining NE does not completely breakdown until after metaphase (d) Mammalian cells are higher eukaryotes that undergo open mitosis where the NE completely dissassembles allowing cytoplasmic spindles to access the chromosomes