Cloning and expression throughout mouse development ofmfat1, a homologue of theDrosophila tumour suppressor genefat

Abstract

We present the entire sequence of the mouse Fat orthologue (mFat1), a protein of 4,588 amino acids with 34 cadherin repeats, 27 potential N‐glycosylation sites, five EGF repeats and a laminin A G‐motif in its extracellular domain. A single transmembrane region is followed by a cytoplasmic domain containing putative catenin‐binding sequences. mFat1 shows high homology to human FAT and lesser homology to Drosophila Fat. The sequence of this giant cadherin suggests that it is unlikely to have a homophilic adhesive function, but may mediate heterophilic adhesion or play a signalling role. Expression analysis shows that the mfat1 gene is expressed early in pre‐implantation mouse development, at the compact eight cell stage. Whole‐mount and section in situ analyses show that transcripts are widely expressed throughout post‐implantation development, most notably in the limb buds, branchial arches, forming somites, and in particular in the proliferating ventricular zones in the brain, being down‐regulated as cells cease dividing. RT‐PCR detects widespread expression in the adult suggesting a role in proliferation and differentiation of many tissues and cell types. Dev Den;217:233–240.