A phenylalanine hydroxylase gene from the nematode C-elegans is expressed in the hypodermis

We have identified an aromatic amino acid hydroxylase gene from the nematod e C. elegans that likely encodes the worm phenylalanine hydroxylase (PheH). The predicted amino acid sequence is most similar to that of other PheH an d TrpA proteins. Reporter gene fusions and staining with an antibody to mam malian PheH indicate the gene is expressed in hypodermal cells. A fusion pr otein expressed in bacteria can convert phenylalanine to tyrosine, and, to a lesser extent, tryptophan to 5-hydroxytryptophan. We hypothesize that the protein is necessary to produce additional tyrosine for protein crosslinki ng in the nematode cuticle.