Figure 1. "Dark" colonies are formed from dissociated one-week-old murine liver or pancreas in our 3D colony assays.

A: Schematic of an in vitro methylcellulose-based colony assay for progenitor cells. Two different colony assays were used in this report: one contained Matrigel and the other laminin hydrogel. B-E: Morphologically distinct colonies are identified when observed under a phase-contrast light microscope one week after plating. B: A photomicrograph of a Dark colony developed from dissociated murine ES cell-derived day-16 cultures, which confirms our prior finding [25]. Dark colony grown in Matrigel (C) or laminin hydrogel (D) from dissociated postnatal liver. E: Dark colony grown in laminin hydrogel from dissociated postnatal pancreas. Abbreviation: mESC - mouse embryonic stem cells.