Fig. 5: Pdk1 upregulation is sufficient and necessary for regenerative growth and proliferation.
From: A JAK/STAT-Pdk1-S6K axis bypasses systemic growth restrictions to promote regeneration
A, B OPP incorporation in control (A) and wing discs expressing Pdk1 for 24 h using rn-GAL4 (B). DAPI visualises nuclei. Line indicates boundary of pouch based on landmark folds, approximating the rn-GAL4 domain. C, D EdU incorporation in control (C) and discs expressing UAS-Pdk1 for 24 using rn-GAL4 (D). The line indicates the boundary of the rn-GAL4 expression domain. E. Mean OPP intensity in the pouch of control and Pdk1-expressing wing discs. Mean and 95% CI, two-tailed Unpaired t test, p-value < 0.0001 (control: n = 6, Pdk1-expressing disc: n = 6). F Mean EdU intensity per DAPI area as proxy for relative DNA replication speed, in control and Pdk1-expressing pouches. Mean and 95% CI, two-tailed Welch’s t test, p-value = 0.0078 (control: n = 8, Pdk1-expressing disc: n = 8). G–J OPP incorporation in control (G, H) and egr-expressing wing discs (I, J), either wild type (G, I) or heterozygous mutant for the Pdk15 null allele (H, J). K Mean OPP intensity in the pouch of control or proliferative domain of egr-expressing discs (PDegr), either wild type or heterozygous mutant for Pdk15 null allele. Mean and 95% CI, One-way ANOVA followed by Tukey’s post-hoc test for multiple comparisons. (control:n = 6, control, Pdk15/+: n = 6; egr:n = 8, egr, Pdk15/+: n = 7). PDegr vs PDegr: Pdk15/+: p-value = 0.0300 and Control: Pdk15/+ vs PDegr: Pdk15/+: p-value = 0.0350. L, M DUAL Control system (DCS) allows to manipulate the proliferative domain. A single heat shock activates both egr-expression in the salm-domain (tracked by pyknotic nuclei and MMP-1 upregulation) and genetic manipulation in the proliferative domain via dve-GAL4 (tracked by UAS-GFP co-expression in L). MMP1 is a target gene of JNK activated by Egr, approximating the domain of salm>egr. Dve-GAL4 expresses in the pouch and pouch fold, morphological landmarks approximating the dve-GAL4 domain driving expression of Pdk1-RNAi (M) for 24 h. Protein synthesis is visualised by OPP incorporation in control (L) and Pdk1-RNAi (M) discs. N Mean OPP intensity in the proliferative domain of control (DCSegr, ctrl) and Pdk1 knockdown (DCSegr, Pdk1 RNAi) discs with egr-expression in the salm-domain. A schematic of the egr-expressing region (cyan, trackable by cell death and MMP-1) and the dve-GAL4-expressing region (magenta, trackable by UAS-GFP co-expression) used for Pdk1 knockdown. Mean and 95% CI, two-tailed unpaired t test (p < 0.0001). (DCSegr, control: n = 10; DCSegr, Pdk1 RNAi: n = 9). O Scheme highlighting the Pdk1-branch driving S6K activation. Scale bars: 100 μm. DAPI visualises nuclei. Fluorescence intensities are reported as arbitrary units. Source data in graphs are provided as a Source Data file. Illustrations were created in Biorender Classen, A. (2025) https://BioRender.com/h63vwwi.
