Localized and transient transcription of Hox genes suggests a link between patterning and the segmentation clock
During development, Hox gene transcription is activated in presomitic mesoderm with a time sequence that follows the order of the genes along the chromosome. Here, we show that Hoxd1 and other Hox genes display dynamic stripes of expression within presomitic mesoderm. The underlying transcriptional bursts may reflect the mechanism that coordinates Hox gene activation with somitogenesis. This mechanism appears to depend upon Notch signaling, as mice deficient for RBPJk, the effector of the Notch pathway, showed severely reduced Hoxd gene expression in presomitic mesoderm. These results suggest a molecular link between Hox gene activation and the segmentation clock. Such a linkage would efficiently keep in phase the production of novel segments with their morphological specification.
Department of Zoology and Animal Biology, University of Geneva, Sciences III, Quai Ernest Ansermet 30, 1211 Geneva 4, Switzerland.
Record created on 2008-02-25, modified on 2016-08-08