Skip to main content
. Author manuscript; available in PMC: 2015 Aug 1.
Published in final edited form as: Nat Cell Biol. 2015 Jan 19;17(2):113–122. doi: 10.1038/ncb3091

Figure 1. Primary cilia arise in the post-implantation epiblast.

Figure 1

Embryos homozygous for the ARL13B-mCherry (red) and Centrin2-GFP (green) transgenes reveal the distribution of centrosomes and primary cilia in the early mouse embryo. (A–D) Preimplantation embryos. (A) Optical section of 32 cell early blastocyst (e3.25); dotted line surrounds ICM. (B) Expanded view of the dashed box in (A) shows that Centrin2-GFP positive centrioles are present on both trophectoderm cells (TE) and inner cell mass cells (ICM), arrows. No primary cilia are observed (Representative image selected from 4 embryos). (C) Optical section of a 72 cell blastocyst (e3.75); dotted line surrounds ICM. No cilia were detected on trophectoderm cells (0 cilia/255 cells from 9 embryos). (D) Expanded view of dashed box shown in (C) shows a rare example (2/107 cells scored from 9 embryos) of ARL13B-mCherry (arrow) expression adjacent to a Centrin2-GFP+ centriole of an ICM cell; these puncta did not have the morphology of cilia nor did they express acetylated α-tubulin. (E–H) Early postimplantation embryos. (E) Longitudinal optical section of e5.5 cavitating embryo; dotted line surrounds the epiblast. (F) Expanded view of the box in (E) shows a rare cilium on an epiblast cell (3/654 cells from 10 embryos). (G) Transverse optical section on an e6.0 embryo, with cilia exclusively on epiblast cells (388/1039 cells from 6 embryos). (H) Expanded view of dashed box in (G) shows cilia (arrows) on epiblast cells; no cilia are present on Centrin2-GFP labeled centrioles in visceral endoderm cells (asterisks; 0/837 cells from 6 embryos). Dotted line denotes boundary between epiblast (below) and visceral endoderm (above). (I) Primary cilia are detected on nearly all cells of the e8.0 embryo. (J, K) Expanded views of dashed boxes in (I) show the cilia in the definitive endoderm (J) and node (K). (L, M) Sections of e10.5 embryos. Cilia are detected in nearly all cells in the limb mesenchyme (L). Neural progenitors extend cilia into the lumen of the neural tube (M). Nuclei are marked with DAPI (blue). Scale bars: (A, B): 10 µm; (C): 8 µm; (D): 2 µm (E): 20 µm; (F): 5 µm; (G, H): 20 µm; (I) 30 µm; (J, K): 10 µm; (L, M) 5 µm. P = posterior, A = anterior, Pr = proximal, D = distal.