Fibronectin Type III Domain Containing Protein 4 (FNDC4)

The putative 219-amino acid protein contains an N-terminal signal peptide, a fibronectin type III domain, and a transmembrane domain. Northern blot analysis of multiple mouse tissues detected 2 Fndc4 transcripts of approximately 2 and 3 kb, with highest expression in adult brain and liver, and low expression in heart, lung, kidney, and testis.

The transcripts were expressed at similar levels in most tissues except liver, where the 2-kb transcript was expressed much more strongly. Northern blot analysis of mouse embryonic mRNA revealed strongest expression of Fndc4 at embryonic day 11 and decreasing expression at E17. In situ hybridization demonstrated expression of Fndc4 in the fore- and midbrain, and extending into the hindbrain.