R. Suzuki et al., Identification of RALDH-3, a novel retinaldehyde dehydrogenase, expressed in the ventral region of the retina, MECH DEVEL, 98(1-2), 2000, pp. 37-50
In the developing retina, a retinoic acid (RA) gradient along the dorso-ven
tral axis is believed to be a prerequisite for the establishment of dorso-v
entral asymmetry. This RA gradient is thought to result from the asymmetric
al distribution of RA-generating aldehyde dehydrogenases along the dorso-ve
ntral axis. Here, we identified a novel aldehyde dehydrogenase specifically
expressed in the chick ventral retina, using restriction landmark cDNA sca
nning (RLCS). Since this molecule showed enzymatic activity to produce RA f
rom retinaldehyde, we designated it retinaldehyde dehydrogenase 3 (RALDH-3)
. Structural similarity suggested that RALDH-3 is the orthologue of human a
ldehyde dehydrogenase 6. We also isolated RALDH-1 which is expressed in the
chick dorsal retina and implicated in RA formation. Raldh-3 was preferenti
ally expressed first in the surface ectoderm overlying the ventral portion
of the prospective eye region and then in the ventral retina, earlier than
Raldh-1 in chick and mouse embryos. High level expression of Raldh-3 was al
so observed in the nasal region. In addition, we found that Pax6 mutants ar
e devoid of Raldh-3 expression. These results suggested that Raldh-3 is the
key enzyme in the formation of an RA gradient along the dorso-ventral axis
during the early eye development, and also in the development of the olfac
tory system. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.