Expression of two novel mouse Iroquois homeobox genes during neurogenesis.
Members of the Drosophila Iroquois homeobox gene family are implicated in the development of peripheral nervous system and the regionalization of wing and eye imaginal discs. Recent studies suggest that Xenopus Iroquois homeobox (Irx) genes are also involved in neurogenesis. Three mouse Irx genes, Irx1, Irx2 and Irx3, have been previously identified and are expressed with distinct spatio-temporal patterns during neurogenesis. We report here the cloning and expression analysis of two novel mouse Irx genes, Irx5 and Irx6. Although Irx5 and Irx6 proteins are structurally more related to one another, we find that Irx5 displays a developmental expression pattern strikingly similar to that of Irx3, whereas Irx6 expression resembles that of Irx1. Consistent with the notion that Mash1 is a putative target gene of the Irx proteins, all four Irx genes display an overlapping expression pattern with Mash1 in the developing CNS. In contrast, the Irx genes and Mash1 are expressed in complementary domains in the developing eye and olfactory epithelium.
Cohen
D R
DR
Program in Developmental Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.
Cheng
C W
CW
Cheng
S H
SH
Hui
C C
CC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D009474:Neurons / Q000502:physiology*; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000235:genetics*
D018076:DNA, Complementary; D018398:Homeodomain Proteins; C501606:IRX3 protein, Xenopus; C501592:Irx1 protein, mouse; C501596:Irx2 protein, mouse; C501599:Irx3 protein, mouse; C501601:Irx5 protein, mouse; C501605:Irx6 protein, mouse; D014157:Transcription Factors