Evx1 is a mammalian gene located downstream of the HoxA cluster, which encodes for a homeobox transcription factor. Evx1 is a homolog of even-skipped (eve), which is a
pair-rule gene
A pair-rule gene is a type of gene involved in the development of the segmented embryos of insects. Pair-rule genes are expressed as a result of differing concentrations of gap gene proteins, which encode transcription factors controlling pair-r ...
that regulates body segmentation in Drosophila. The expression of Evx1 is developmentally regulated, displaying a biphasic expression pattern with peak expression in the
primitive streak
The primitive streak is a structure that forms in the early embryo in amniotes. In amphibians the equivalent structure is the blastopore. During early embryonic development, the embryonic disc becomes oval shaped, and then pear-shaped with the br ...
during
gastrulation
Gastrulation is the stage in the early embryonic development of most animals, during which the blastula (a single-layered hollow sphere of cells), or in mammals the blastocyst is reorganized into a multilayered structure known as the gastrula. ...
and in interneurons during neural development.
Evx1 has been shown to regulate anterior-posterior patterning during gastrulation by acting as a downstream effector of the
Wnt and BMP signalling pathways.
It is also a critical regulator of
interneuron
Interneurons (also called internuncial neurons, relay neurons, association neurons, connector neurons, intermediate neurons or local circuit neurons) are neurons that connect two brain regions, i.e. not direct motor neurons or sensory neurons. ...
identity.
Despite a regulatory role in both of these processes, the Evx1 KO mouse is viable and displays no overt phenotype after birth.
A divergent
long non-coding RNA (Evx1as) is also expressed from the locus, which is temporally and spatially co-expressed with Evx1.
Evx1as does not have a function beyond that of Evx1 (in trans);
however, it has been shown to regulate Evx1 at the locus (in cis).
References
{{Transcription factors and intracellular receptors, g3
Genes