Fig. 3: The diffusible fraction of Dpp prevents de-differentiation.

A Asymmetric and symmetric outcomes of GSC division. Symmetric outcome is defined as the case in which two daughter cells from a GSC division are both placed near the hub, resulting in the production of two GSCs. It occurs as the consequence of either symmetric division¹ or de-differentiation² (see details in main text). B, C Representative images of testis tip without (B) or with (C) trapping Dpp. Broken lines indicate asymmetric events in (B) and a symmetric event in (C). D Frequency of testes showing any symmetric events (number of testes/scored testes) without or with trapping Dpp. E Changes in GSC number across post-eclosion without or with trapping Dpp. F, G Representative images of testis tip after depletion of GSC by expressing Bam at 0-day recovery (0D recov: immediately after 6-time heat shock treatment) and after 3-day and 5-day recovery time points (3D recov, 5D recov) in room temperature culture without (F) or with (G) trapping Dpp. H Changes in GSC number during recovery from forced differentiation of GSCs without or with trapping Dpp. Pre: pre-heat shock. I Frequency of GSCs (number of GSCs/scored GSCs) with misoriented centrosome or spindle without or with trapping Dpp. J–M Representative images of centrosomes in interphase cells (J, K) and mitotic cells (L, M) of GSCs without (J, L) or with (K, M) trapping Dpp. For trapping Dpp in this figure, Nrv-Morphotrap was expressed under the control of fasIIIGal4 driver in mGL-dpp homozygous background rescued by pPA dpp 8391/X. Siblings without Gal4 were used for the control. Fixed samples were used for all images and graphs. All scale bars represent 10 μm. Asterisks indicate the approximate location of the hub. n indicates the number of scored testes in D, E and H, or scored GSCs in I. Box plots show 25–75% (box), minimum to maximum (whiskers) with all data points. The p-value was calculated by two-tailed student-t-test for D and I and by Šídák’s multiple comparion tests for E and H and provided on each graph. Source data for E, H are provided in Source Data file.