Abstract: Objective To investigate the role H3K27me3 demethylase JMJD3(KDM6B) during the development of lung in embryonal mice. Methods Jmjd3 knockout embryos of E19.5 mice was examined by HE, PAS and immnohistochemistry assays. Results The developmental defects of the lung of Jmjd3 heterozygous (Jmjd3+/?) embryos were mild compared to Jmjd3+/+ embryos. However, Jmjd3?/? mice suffered from the severe hypoplasia of lung tissue. Differentiated defects of ciliated cell, Clara cell, type I and II alveolar epithelial cells were observed in Jmjd3?/? embryos. The index of cell proliferation was increased in Jmjd3?/? embryos compared to wildtype and Jmjd3+/? embryos. No difference of apoptosis was detected in these embryos. Conclusion JMJD3 is indispensable for proliferation and differentiation of embryonal lung epithelia of mice.

Key words: JMJD3, epithelia of lung, proliferation, differentiation