Figure 3.
Cerebellar Granule Progenitors Undergo Both Symmetric and Asymmetric Divisions Ex Vivo
(A) Ten selected frames from Movie S4, a 1.5-hr time-lapse sequence of GN progenitor cells. Images show that a MATH1-GFP cell on the left (blue arrow) undergoes symmetric division, generating two MATH1-GFP progenitors (blue arrow).
(B) Eight selected frames from Movie S5, a 1-hr time-lapse sequence. Images show that a MATH1-GFP cell on the left (blue arrow) undergoes asymmetric division, generating one MATH1-GFP progenitor (blue arrow) and one MATH1 and DCX co-expressing cells (white arrow).
(C) Sixteen selected frames from Movie S6, a 2-hr time-lapse sequence. Images show that a MATH1-GFP cell (blue arrow) undergoes symmetric division, generating two MATH1-GFP progenitors (blue arrow). Subsequently, one MATH1-GFP cell on the bottom (blue arrow) slowly turns to yellow (white arrow). Afterward, another MATH1-GFP cell on the top gradually becomes a yellow cell (white arrow). Lastly, both yellow cells change to red, indicating that progenitor cells undergo terminal symmetric division, which is different from the non-terminal symmetric division in (A). Scale bars, 10 μm.
(D) Statistical analysis shows that the ratio of non-terminal symmetric-to-asymmetric-to-terminal symmetric division was 22.09%:4.33%:73.58% at P10, while all progenitor cells undergo symmetric division at P4 (images not shown).
The data we collected were from 77 dividing cells, which were traced from three independent experiments. Data are shown as mean ± SEM. ∗∗∗p < 0.001, referring to the number of non-terminal symmetric divisions at P4 versus P10.