First, among genes that were expressed at higher levels in the advanced rudiment stage, we found enriched categories related to RNA and DNA metabolism, RNA processing, and cell division (supplementary table S1, Supplementary Material online).
The embryonic DCL comprised 100 120 relatively small cells (Fig. 2b) that doubled their number after a round of asynchronous cell division (Supplementary Fig. 1a) and progressively increased the mean distance with their immediate neighbours (Fig. 2d; Supplementary Fig. 1b).
During this period, the extra-embryonic EVL contained 50 60 polygonal-shape cells of variable size that progressively expanded their surface area (Fig. 2b) without events of cell division (Supplementary Movie 1).
To avoid a biased estimate of aneuploidy due to the limited number of sequenced nuclei, we observed microscopically three aspects of chromosome instability: chromosome deletion, duplication, and lagging during cell division (Supplementary Fig. 7) at the meiotic stage by using three fluorescent markers on chromosomes 2, 4 and 6.
In addition, we noted higher Chop levels in proliferating transferred Pmel T cells from gp10025 33-vaccinated mice (activation-driven T cell proliferation) compared to non-vaccinated cohorts (homeostatic T cell division) (Supplementary Figp10025 33-vaccinatede increased expression of Chop under activation-induced CD8+ T cell proliferation.
The CCR9 molecule was indeed strongly up-regulated in OT-1 T cells after cell division (Supplementary Figure S1).
When IPTG and rapamycin were washed out, there was a lag period about 24-30 hrs for competent cells to undergo first division (supplementary movie will be available at).
Based on a 50% (0.33 log10) decline in H2B-GFP levels with every cell division (supplementary material Fig. S2F,G), ∼40% of the SC pool undergoes ∼2 divisions (LRCs), whereas the remainder undergo ∼4 divisions (nonLRCs) between E16.5 and P1.
aPKC inhibition does not prevent cell division (supplementary material Movies 5, 6); however, there is an increase in the apoptosis:cell-division ratio that affects the expansion of the PrE (Fig. 4G).
Cells with partial/punctate EdU signal were not considered to be label-retaining cells since dilution of signal indicates that cells have undergone cell division (supplementary material Fig. S1B).
The signals at the phragmoplast decreased during subsequent cell divisions (Supplementary Movie 3).
