摘要
Spatiotemporal regulation of cell proliferation is necessary for normal tissue development. The molecular mechanisms, especially the signaling pathways controlling the cell cycle machinery, remain largely unknown. Here, we demonstrate a negative relationship between the spatiotemporal patterns of
jumonji (
jmj) expression and cardiac myocyte proliferation.
cyclin D1 expression and cell proliferation are enhanced in the cardiac myocytes of
jmj-deficient mutant embryos. In contrast,
jmj overexpression represses
cyclin D1 expression in cardiac cells, and Jmj protein binds to
cyclin D1 promoter in vivo and represses its transcriptional activity.
cyclin D1 overexpression causes hyperproliferation in the cardiac myocytes, but the absence of
cyclin D1 in
jmj mutant embryos rescues the hyperproliferation. Therefore, Jmj might control cardiac myocyte proliferation and consequently cardiac morphogenesis by repressing
cyclin D1 expression.