Figure EV1. Expression level of igfbp1a in mosaic over‐expressing larvae and stable transgenic lines.

• A, B
  Relative igfbp1a mRNA levels in mosaic bactin:igfbp1a transgenic larvae. Control or bactin:igfbp1a‐injected embryos were collected for RNA purification and qPCR analysis at 4 dpf (A) or 6 dpf (B). Igfbp1a expression was approximately 80 times higher in bactin:igfbp1a overexpressing larvae than in control larvae. ***P < 0.0001 and **P = 0.0024. Each data point represents one larva; thus, it can be seen that substantial Igfbp1a overexpression was attained in all bactin:igfbp1a‐injected embryos that generated mosaically overexpressing larvae.
• C–F
  Relative igfbp1a mRNA levels (C, E) in two independent stable Tg(bactin:igfbp1a) lines, which have the line designations KI103 and KI104. Control and Tg(bactin:igfbp1a) larvae were processed for qPCR analysis at 6 dpf. Both transgenic lines (data for each line are shown separately, in panels C and E) have moderately, but significantly, higher expression of igfbp1a than sibling controls; *P = 0.0121 and ***P = 0.0007, respectively. (D, F) Like the larvae mosaically overexpressing igfbp1a, the stable Tg(bactin:igfbp1a) lines also have an increase in β‐cell regeneration. We crossed the Tg(bactin:igfbp1a) lines into the double transgenic Tg(ins:H2B‐GFP);Tg(ins:Flag‐NTR) to allow visualization of β‐cell regeneration. We treated the resulting offspring with metronidazole (MTZ) from 3 to 4 dpf to ablate the β cells and then allowed them to regenerate until 6 dpf. Both Tg(bactin:igfbp1a)^KI103 and Tg(bactin:igfbp1a)^KI104 stable lines had a significant increase in β‐cell regeneration (*P = 0.0121 and *P = 0.0107, respectively).

Data information: Results are presented as mean and individual values and analyzed with t‐tests (A, B) or Mann‐Whitney tests (C–F). Related to Fig 1.