Identification of starmaker-like in medaka as a putative target gene of Pax2 in the otic vesicle.

Otoliths in bony fishes are involved in the function of the ear in the senses of balance and hearing. In a large-scale random in situ hybridization screen of genes expressed in the medaka developing ear, we identified starmaker-like (stm-l) gene, a novel homologue of zebrafish starmaker and human dentine sialo-phosphoprotein (dspp) gene. Despite the absence of sequence similarity between these genes, here we describe their similar genomic structure and expression patterns hinting for a conserved function. In medaka fry, stm-l is expressed in various organs such as otoliths, teeth, gills, and kidney. Additionally, our results provide evidence that stm-l is a putative downstream target gene of Pax2 transcription factor and Pax2 itself has a promoting function in otolith formation. Copyright 2009 Wiley-Liss, Inc.