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Show posters on the hill Microtubule Associated Proteins (MAPS) are Required for Amphibian Development Josh Plant, Dave Gard Department of Biology .icrotubules play important roles in cell shape, division, and motility. Microtubules are dynamic polymers composed of u- and f-tubulin dimmers. Microtubules are either growing or shrinking by a process known as dynamic instability, which allows the cell to search in space (i.e. for chromosome capturing during mitosis). MAPs (microtubule associated proteins) bind to the sides of microtubules and modulate the organization and dynamics both in vitro and in vivo. Microtubules play several important roles during early development in the African clawed frog Xenopus laevis. For example microtubules play an essential role in the specification of the dorsal-ventral axis and are required for the formation of axons and dendrites in neural cells. Therefore, microtubule dynamics and organization must be regulated both temporally and spatially. XMAP215 is a unique MAP present in Xenopus oocytes, eggs, and early embryos and is a member of an ancient family of MAPs. Unlike other known MAPs XMAP215 promotes microtubule dynamics in vitro and is required for microtubule growth and organization in vivo. Microtubule Associated Proteins (MAPS) are Required for Amphibian Development Josh Plant, Dave Gard Department of Biology To address the role ofXMAP215 during development we prevented the translation of XMAP215 by injecting anti-sense morpholino oligos in one cell of a two cell embryo. Embryos injected with XMAP215 morpolinos failed to complete gasturlation resulting in the injected half dying. Further analysis showed defects in cell division with abnormal cell size and morphology. Furthermore, injected embryos had a high number of mul-tipolar spindles. These results suggest that XMAP215 is required for proper spindle assembly in Xenopus embryos. Large cell size and unusual cell morphology indicate failed mitosis which leads to a di- minished cell population. Due to the decreased number of cells this prevented the ectoderm from migrating around the endoderm during gasturlation. |