The cap 'n' collar family member NF-E2-related factor 3 (Nrf3) is expressed in mesodermal derivatives of the avian embryo

NF-E2-related factor 3 (Nrf3) is a recently identified member of a family of transcription factors homologous to the Drosophila << cap'n'collar >> or CNC protein. The cnc gene is located immediately 3' to the Drosophila homeobox gene cluster and has been shown to regulate at least one of those genes, deformed Likewise, human and mouse CNC homologues are located immediately 3' to each of the four Hox complexes, although no genetic interactions have yet been demonstrated in vertebrates. Work presented here demonstrates that Nrf3, adjacent to the Hox A cluster, is expressed during early development of the chicken embryo. Expression begins in the presumptive heart myocardium from the time of cardiac tube fusion through the looping process. Nrf3 transcripts then disappear from the heart and are next observed in the myotomal compartment of maturing somites, restricted to the medial portion along the rostrocaudal axis and fading after muscle precursors migrate. Central nervous system expression appears gradually and persists at low levels in ventricular neuroepithelial cells until at least embryonic day 6. Strong expression is observed in the early epiphysis, in the collecting ducts of the developing kidney and in individual cells of the yolk sac, underlying blood islands. This is the first description using in situ hybridization of the expression of a CNC family member and its dynamics through the course of early development.