Fig. 3

Variant key development regulators highly suggest different cellular origins of β cell regeneration. (A–L) Merged and single-channel confocal planes of primary islets after DMSO or Mtz treatment. Tg(ins:CFP-NTR) was used to label β cell blue with CFP and perform ablation. Single or double transgenic lines were combined to mark specific β cell development regulators green with GFP. White arrows indicated GFP-positive β cells. White arrowheads indicated GFP-negative β cells. Scale bar, 10 μm. Tg(pdx1:GFP) marked pdx1+ cells. β cells in the DMSO-treated control group were all pdx1+ (A, n = 35/35). In contrast, some β cells were not pdx1+ in the Mtz-treated group (B, n = 33/38). Tg(mnx1:GFP) marked mnx1+ cells. Not all β cells were mnx1+ in either the control or Mtz-treated groups (C, n = 22/22; D, n = 22/26). Tg(nkx2.2a:GFP) marked nkx2.2a+ cells. Not all β cells were nkx2.2a+ in either control or Mtz-treated groups (E, n = 21/21; F, n = 20/23). Tg(pdx1:GFP; mnx1:GFP) marked pdx1+, mnx1+, or pdx1+mnx1+ cells. All β cells were GFP positive in both the control and Mtz-treated groups (G, n = 34/34; H, n = 37/37). Tg(pdx1:GFP; nkx2.2a:GFP) marked pdx1+, nkx2.2a+, or pdx1+nkx2.2a+ cells. All β cells were GFP positive in both the control and Mtz-treated groups (I, n = 20/20; J, n = 23/25). Tg(mnx1:GFP, nkx2.2a:GFP) marked mnx1+, nkx2.2a+, or mnx1+nkx2.2a+ cells. Not all β cells were GFP positive in either the control or Mtz-treated groups (K, n = 21/21; L, n = 26/29). (M) Quantifications of ratios of β cells that were GFP positive in the primary islets after DMSO or Mtz treatment with listed transgenic lines (DMSO-treated control groups: mnx1+, n = 5; all the other groups, n = 3. Mtz-treated groups: neurod+, n = 4; pdx1+, n = 17; mnx1+, n = 8; nkx2.2+, n = 6; pdx1+, mnx1+, or pdx1+mnx1+, n = 18; pdx1+, nkx2.2a+, or pdx1+nkx2.2a+, n = 5; mnx1+, nkx2.2a+, or mnx1+nkx2.2a+, n = 8. Mean ± s.e.m. All tested by two-tailed Student's t-test.). Color images are available online.