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Video 4
The behavior of centrioles and MTs in a cnn embryo during mitosis. Images from this embryo are shown in Fig. 2 (A-D). Centrioles are visualized with mRFP-PACT (red), and the MTs are visualized with GFP-α-tubulin (green). This video shows an enlarged area of the same embryo shown in Video 3. The centrioles visualized with mRFP-PACT are very small, so most of the centrioles in this video are out of the plane of focus, although their position can be inferred from the position of the MT asters they nucleate. The centriole marked with the large arrow is closely associated with a spindle pole as the embryo proceeds through mitosis; this pole is therefore associated with astral MTs. The centriole marked with a small arrow is initially not in the focal plane of this video; it associates with a forming spindle pole but then migrates into the spindle and then back out to the spindle pole. The centriole marked with an arrowhead is out of the focal plane of this video; the astral MTs it organizes are initially associated with the pole of a spindle, but these then migrate off into the cytoplasm. Note how the spindle pole becomes anastral as the centriole moves away. Images were collected every 3 s and are displayed at 20 fps.