Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-3340
Genes Dev 2004 Jul 15;1814:1725-36. doi: 10.1101/gad.303504.
Show Gene links Show Anatomy links

The mouse homeobox gene Not is required for caudal notochord development and affected by the truncate mutation.

Abdelkhalek HB , Beckers A , Schuster-Gossler K , Pavlova MN , Burkhardt H , Lickert H , Rossant J , Reinhardt R , Schalkwyk LC , Müller I , Herrmann BG , Ceolin M , Rivera-Pomar R , Gossler A .


???displayArticle.abstract???
The floating head (flh) gene in zebrafish encodes a homeodomain protein, which is essential for notochord formation along the entire body axis. flh orthologs, termed Not genes, have been isolated from chick and Xenopus, but no mammalian ortholog has yet been identified. Truncate (tc) is an autosomal recessive mutation in mouse that specifically disrupts the development of the caudal notochord. Here, we demonstrate that truncate arose by a mutation in the mouse Not gene. The truncate allele (Nottc) contains a point mutation in the homeobox of Not that changes a conserved Phenylalanine residue in helix 1 to a Cysteine (F20C), and significantly destabilizes the homeodomain. Reversion of F20C in one allele of homozygous tc embryonic stem (ES) cells is sufficient to restore normal notochord formation in completely ES cell-derived embryos. We have generated a targeted mutation of Not by replacing most of the Not coding sequence, including the homeobox with the eGFP gene. The phenotype of NoteGFP/eGFP, NoteGFP/tc, and Nottc/tc embryos is very similar but slightly more severe in NoteGFP/eGFP than in Nottc/tc embryos. This confirms allelism of truncate and Not, and indicates that tc is not a complete null allele. Not expression is abolished in Foxa2 and T mutant embryos, suggesting that Not acts downstream of both genes during notochord development. This is in contrast to zebrafish embryos, in which flh interacts with ntl (zebrafish T) in a regulatory loop and is essential for development of the entire notochord, and suggests that different genetic control circuits act in different vertebrate species during notochord formation.

???displayArticle.pubmedLink??? 15231714
???displayArticle.pmcLink??? PMC478193
???displayArticle.link??? Genes Dev


Species referenced: Xenopus
Genes referenced: foxa2 not tbxt

References [+] :
Ades, Differential DNA-binding specificity of the engrailed homeodomain: the role of residue 50. 1994, Pubmed