The Journal of Neuroscience, November 16, 2005, ():
Gap Junctions Modulate Interkinetic Nuclear Movement in Retinal Progenitor Cells
J. Neurosci. Pearson et al.
25: 10803
Supplemental data
Files in this Data Supplement:
- supplemental material
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Figure 1: The cell cycle in the chick retina. A, The nucleus of a progenitor cell (PC, gray) moves between the ventricular zone, which is permissive for mitosis (M) (Robinson et al., 1985), and the vitreal surface. The nucleus moves toward the vitreal surface in G1, replicates its DNA (S-phase) and returns to the ventricular zone in G2. Progenitor cells undergo either symmetric division, in which both daughter cells continue in the cell cycle, or divide asymmetrically, giving rise to a progenitor cell and a post-mitotic cell (PMC, black) that then migrates to its final location. B, DiI labeling of retinal cells. Image is a rotated projection of a stack of 100 images taken at 1μm steps. Scale bar 10μm.
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Figure 2: Ratiometric measurements of spontaneous Ca2+ transients in a progenitor cell undergoing interkinetic nuclear movement. A, A series of dual-emission xz confocal images through a retina labelled with Oregon Green (green) and Indo-1 (blue). The cell highlighted undergoes a spontaneous Ca2+ transient. B, Changes in fluorescence intensity of Oregon Green (green line) and Indo-1 (blue line) taken from the region shown in A. Upward deflections in Oregon Green and downward deflections in Indo-1, respectively, represent an increase in [Ca2+]i. AU = arbitrary units. C, Time-course of changes in the ratio of Oregon Green/Indo-1 fluorescence signal. Upward deflections in ratio signals represent an increase in [Ca2+]i. D, the distance traveled by the nucleus as a function of time.
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Figure 3. Model for gap junction-mediated regulation of interkinetic nuclear movement. In uncoupled cells (left), nuclear translocation is driven by the spontaneous Ca2+ transients occurring within the individual cell. However, when cells are coupled via gap junctions, Ca2+ transients can spread between neighbors (right). Thus, each of the cells within the coupled cluster experiences the transients that occur in its neighbors.
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Movie 1: Interkinetic nuclear movement in the E5 chick retina. The preparation was labelled with DiI using immersion labelling and imaged using confocal microscopy. Z-stacks through the thickness of the retina were acquired at 15min intervals over a period of 5.5h. The resulting 3D stacks were rotated through 90 degrees to give a side-on projection view; this was repeated for each time point and assembled to produce a time-lapse movie. Four cells (or pairs of cells) are highlighted by numbers (left). Asterisks mark the position of the respective nucleus in the first frame. The nucleus of cell 1 undergoes saltatory movements in both directions at an average rate of 15µm/hour, and rounds up on approach to the VZ, towards the end of the time-series. The nucleus moves a total of 42µm towards the VZ from first to last frame. The nucleus of cell 2 makes saltatory movements away from the VZ, towards the vitreal surface, at an average rate of 11µm/hour. The nucleus of cell 3 moves rapidly towards the VZ during the first 6 frames (average rate of 45µm/hour), rounding up as it does so, and undergoes mitosis during frames 7-10. The cell maintained its vitreal process throughout division. From frame 11 onwards, two separate daughter cells can be seen moving away from the VZ. Cell pair 4 also undergoes saltatory movements, moving a total of 34µm away from the VZ during the period imaged, the two nuclei maintaining close proximity throughout.
