Developmental regulation of the Hox genes during axial morphogenesis in the mouse

Abstract

The Hox genes confer positional information to the axial and paraxial tissues as they emerge gradually from the posterior aspect of the vertebrate embryo. Hox genes are sequentially activated in time and space, in a way that reflects their organisation into clusters in the genome. Although this co-linearity of expression of the Hox genes has been conserved during evolution, it is a phenomenon that is still not understood at the molecular level. This review aims to bring together recent findings that have advanced our understanding of the regulation of the Hox genes during mouse embryonic development. In particular, we highlight the integration of these transducers of anteroposterior positional information into the genetic network that drives tissue generation and patterning during axial elongation.

Anteroposterior patterning in the limb and digit specification: Contribution of mouse genetics

“…However, ZPA formation must be explained in fine by a generator of positional identity in the limb independent of pre-existing local cues. This might be the HoxD cluster, because Hox clusters are endowed of intrinsic properties to generate patterns along the rostro-caudal axis (Deschamps and van Nes, 2005). However, the current hypothesis is that 5Ј Hoxd genes are repressed anteriorly by Gli3R (Tarchini and Duboule, 2006).…”

“…The Hox clusters are primarily involved in organizing the body plan along the rostrocaudal axis (Deschamps and van Nes, 2005). The HoxA and HoxD clusters (Fig.…”

Epigenetic regulations in hematopoietic Hox code

“…Several upstream regulatory factors have been suggested in modulating Hox gene expression during its anteriorward spreading, such as Wnt, retinoic acid (RA), fibroblast growth factor (Fgf), Krox20 and Kreisler (Deschamps and van Nes, 2005 (Davidson et al, 2003). Accordingly, the Fgf, Wnt, RA-Cdx4-Hoxa9 pathway is proposed to direct the differentiation of the hematopoietic progenitors (Figure 1a).…”

“…The regulation of the patterning of the embryonic trunk and tail is a basic function of the homeobox-containing Hox gene family in Drosophila (Deschamps and van Nes, 2005). However, various downstream targets of Hox genes in the developing central nervous system suggest that Hox genes encoding DNA-binding transcription factors not only play a role in patterning of the central nervous system during early development, but also contribute to cell specification and identity (Akin and Nazarali, 2005).…”

Gene Silencing and Polycomb Group Proteins: An Overview of their Structure, Mechanisms and Phylogenetics

“…In Drosophila, Hox genes are active during early embryogenesis and are maintained during adult life via epigenetic mechanisms. Clustered on chromosomes (Garcia-Fernandez, 2005), the Hox gene family is important for the proper positioning of segmented structures along the body axes (Deschamps and van Nes, 2005). Crosstalk between PcG Cao et al, 2005) and the trithorax (Petruk et al, 2001;Salvaing et al, 2006) genes was first discovered in Drosophila melanogaster.…”