DBHR, a gene with homology to dopamine beta-hydroxylase, is expressed in the neural crest throughout early development

In a screen for genes involved in neural crest development, we identified D BHR (DBH-Related), a putative monooxygenase with low homology to dopamine b eta -hydroxylase (DBH). Here, we describe novel expression patterns for DBH R in the developing embryo and particularly the neural crest. DBHR is an ea rly marker for prospective neural crest, with earliest expression at the ne ural plate border where neural crest is induced, furthermore, DBHR expressi on persists in migrating neural crest and in many, though not all, crest de rivatives. DBHR is also expressed in the myotome, from the earliest stages of its formation, and in distinct regions of the neural tube, including eve n-numbered rhombomeres of the hindbrain. In order to investigate the signal s that regulate its segmented pattern in the hindbrain, we microsurgically rotated the rostrocaudal positions of rhombomeres 3/4. Despite their ectopi c position, both rhombomeres continued to express DBHR at the level appropr iate for their original location, indicating that DBHR is regulated autonom ously within rhombomeres. We conclude that DBHR is a divergent member of a growing family of DBH-related genes; thus, DBHR represents a completely new type of neural crest marker, expressed throughout the development of the n eural crest, with possible functions in cell-cell signaling. (C) 2001 Acade mic Press.