Research Paper Volume 14, Issue 20 pp 8270—8291

Figure 5. Cycling OKSM expression maintains a larger pool of intestinal stem cells over time. We visualized and quantified stem cells using β-catenin-GFP (arm^GFSTF) which appeared enriched in ISCs. Flies cycled expression through temperature shifts from 18° to 25° for twelve hours twice per week. (A) arm^GFSTF; armGal4; tubGal80^ts > UAS-TdTomato control flies showed a small number of stem cells and few enteroblasts after four weeks. Expression of OKSM (B), Sen (C) or both Sen and OKSM (D) led to an increase in both ISCs with the highest number of ISCs observed in the OKSM condition as quantified (E, F). After eight weeks, the number of ISCs in the OKSM condition was much higher in the OKSM flies as compared to wildtype (G, H) and Sen (I) or Sen; OKSM (J) quantified (K, L). At twelve weeks, OKSM flies maintained high numbers of stem cells while the other conditions (M–P) showed fewer as quantified (Q, R).