RALDH3, a retinaldehyde dehydrogenase that generates retinoic acid, is expressed in the ventral retina, otic vesicle and olfactory pit during mouse development

The enzymes that generate retinoic acid during development have been identi fied as members of the aldehyde dehydrogenase (ALDH) family. The developmen tal expression patterns of two ALDHs that function as retinaldehyde dehydro genases, RALDH1 and RALDH2, have been described. Here we report the cloning and expression of a third retinaldehyde dehydrogenase from the mouse calle d RALDH3 that shares 94% amino acid sequence identity to a human retinaldeh yde dehydrogenase previously named ALDH6. In mouse embryos, RALDH3 expressi on is first noticed in the ventral optic eminence at E8.75, then in the opt ic vesicle/cup, otic vesicle, and olfactory placode/pit from E9.5 to E11.5. Expression in the developing eye is primarily localized in the ventral ret ina, thus indicating that RALDH3 represents the V1 dehydrogenase activity d escribed there earlier. From E8.5 to E10.5 RALDH3 expression is distinct fr om that of RALDH1 or RALDH2, thus indicating a unique role in sensory organ development. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.