Expression of a zebrafish Cathepsin L gene in anterior mesendoderm and hatching gland

During a differential display-based screen for developmentally regulated genes in zebrafish, we have isolated a cDNA for zebrafish cathepsin L, termed catL. The gene shows abundant expression in the anteriormost cells of the head process which give rise to the polster and later to the hatching gland. Expression of catL persists in these tissues until hatching. catL thus provides a useful marker for very anterior mesendodermal structures in zebrafish.