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. Author manuscript; available in PMC: 2014 Apr 10.
Published in final edited form as: Genesis. 2010 Oct 7;48(11):635–644. doi: 10.1002/dvg.20667

FIG. 4.

FIG. 4

Cell-lineage tracing in the cruciate ligaments of the knee joint. Sagittal sections of the knee joint of Sox9LacZ/+embryos and Sox9CreERT2/+;R26R newborn mice from the pregnant females that are injected once with tamoxifen at different time points between E11.5 and E15.5. (a) Sox9 is detected in cartilage primordia of the femur, tibia, and fibula in the knee joint of E13.5 Sox9LacZ/+embryos. The cells of the interzone between the cartilage primordia exhibit Sox9 expression. (b) At E14.5, Sox9 expression is restricted to chondrocytes. (c) At E15.5, the cruciate ligaments form and the ligament cells do not express Sox9. (d) The cruciate ligament cells are positive in the knee joint of E17.0 Sox9Cre/+;R26R embryos. (e–g) The cruciate ligament cells are positive for X-gal after tamoxifen injection at E11.5, E12.5, and E13.5. (h) The number of labeled cells is markedly decreased in newborn mice that are injected with tamoxifen at E14.5. (i) No labeled cells are detected when tamoxifen is injected at E15.5. Fe, Ti, and Fi indicate the cartilage primordia of the femur, tibia, and fibula, respectively. Arrows indicate the cruciate ligaments. Arrow heads indicate X-gal positive cells.