Abstract
In the embryonic mouse retina, retinoic acid (RA) is unevenly distributed along the dorsoventral axis: RA-rich zones in dorsal and ventral retina are separated by a horizontal RA-poor stripe that contains the RA-inactivating enzyme CYP26A1. To explore the developmental role of this arrangement, we studied formation of the retina and its projections in Cyp26a1 null-mutant mice. Expression of several dorsoventral markers was not affected, indicating that CYP26A1 is not required for establishing the dorsoventral retina axis. Analysis of the mutation on a RA-reporter mouse background confirmed, as expected, that the RA-poor stripe was missing in the retina and its projections at the time when the optic axons first grow over the diencephalon. A day later, however, a gap appeared both in retina and retinofugal projections. As explanation, we found that CYP26C1, another RA-degrading enzyme, had emerged centrally in a narrower domain within the RA-poor stripe. While RA applications increased retinal Cyp26a1 expression, they slightly reduced Cyp26c1. These observations indicate that the two enzymes function independently. The safeguard of the RA-poor stripe by two distinct enzymes during later development points to a role in maturation of a significant functional feature like an area of higher visual acuity that develops at its location.
Original language | English |
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Pages (from-to) | 143-157 |
Number of pages | 15 |
Journal | Developmental Biology |
Volume | 276 |
Issue number | 1 |
DOIs | |
Publication status | Published - 1 Dec 2004 |
Keywords
- animals
- body patterning
- cytochrome P-450 enzyme system
- eye
- gene expression regulation, enzymologic
- reporter genes
- mice
- knockout mice
- temporal retina
- tretinoin
- beta-galactosidase
- developing mouse retina
- dorsoventral axis
- CYP26A1
- CYP26B1
- CYP26C1
- retinoic acid homeostasis
- visual streak
- anisotropy
- moon illusion
- retinaldehyde dehydrogenase
- aldehyde dehydrogenase
- human cytochrome-P450
- synthesizing enzyme
- metabolizing enzyme
- active repression
- genetic evidence
- ventral retina