Figure 3.

Wild-Type Cells in a M^−/+ Background Increase Both Proliferation and Symmetric Self-Renewal Rates

(A–B′) WT clones (marked by the absence of GFP) were generated in recently eclosed flies either in control WT (A and A′) (hsflp/+; +/CyO; FRT82B, ubiGFP/FRT82B; denoted as WT/WT) or M^−/+ (B and B′) (hsflp/+; FRT82B, ubiGFP, RpS3/FRT82B; denoted as WT/M^−/+) background, and flies were aged 3 or 20 days prior to dissection.

(C) WT clone-size distributions for 3- and 20-day-old clones with genotypes as indicated. Note that the 3-day distributions do not include single-EB/EC clones (i.e., Dl⁻ single-cell clones), to remove the large number of single EBs/ECs generated by the mitotic recombination event. p: Mann-Whitney test.

(D) Graph showing the average number of negatively labeled WT cells per gut (average clone number^∗average clone size; n > 13 guts for each condition) at 3, 7, and 20 days ACI.

(E and F) EdU incorporation and Dl staining in WT (not shown) or M^−/+ (E) guts harboring WT clones to monitor relative proliferation rates in Dl⁺ ISCs. The bar chart in (F) shows the average proportion of Dl⁺ cells that have incorporated EdU for the indicated genotypes 7 days ACI (n > 9 guts per condition).

(G) Proportion of Dl⁺ cells that have incorporated EdU in M^−/+ cells surrounding WT clones, normalized to the EdU incorporation rate for M^−/+ Dl⁺ cells away from clones (within the same guts). Each dot represents one gut (n = 18 guts).

(H) Bar charts showing how the proportion of Dl⁺/DAPI⁺ cells changes with time in control or competing WT clones at 3, 7, and 14 days ACI. For this comparison, we only considered clones containing at least two cells and Dl⁺ single-cell clones (to filter out the large number of ECs introduced by mitotic recombination; n = number of clones; p: Mann-Whitney test).

Scale bars represent 50 μm. Error bars represent SEM, except for (D), where the error was calculated as described in Supplemental Experimental Procedures. See also Figure S2.