FIG. 3.

LIN28 is expressed in undifferentiated germ cells, but not in those undergoing meiosis. Double immunofluorescence reveals the extensive overlap between the expression domains of LIN28 (green) and OCT4 (red) (A). All OCT4-positive cells express LIN28, although some germ cells are LIN28-positive only (arrows). High-magnification images of the human fetal ovary at 14 wga (B) reveal that LIN28 occupies a distinct subnuclear compartment (arrows) from which OCT4 protein is excluded. No colocalization of LIN28 (green) with the meiosis marker SYCP3 (red) is detected at 15 wga at the periphery (C) or deeper within the cortex (D). No staining is detected on negative controls (insets, A and C). Scale bars in A, C, and D: 50 μm; B: 10 μm, blue staining denotes cell nuclei.