Epigenetic Temporal Control of Mouse Hox Genes in Vivo

Abstract

Hox Clocks Homeobox or Hox genes are historically significant for demonstrating evolutionary conservation and homology in developmentally important genes. In addition, in many species, the Hox genes are fundamental to the organization of the embryo. Modifications in the regulation of their colinear, temporal activation may represent a way of altering their expression patterns and to elaborate body plans during evolution. Soshnikova and Duboule (p. 1320 ) now report highly dynamic modifications of chromatin marks along with progressive Hox gene activation during axial extension in the mouse. This work supports the proposal that the “ Hox clock” may be controlled, at least in part, by epigenetic mechanisms.