Sequestration of retinyl esters is essential for retinoid signaling in the zebrafish embryo

J Biol Chem. 2007 Jan 12;282(2):1144-51. doi: 10.1074/jbc.M609109200. Epub 2006 Nov 10.

Abstract

For vertebrate development, vitamin A (all-trans retinol) is required in quantitative different amounts and spatiotemporal distribution for the production of retinoic acid, a nuclear hormone receptor ligand, and 11-cis retinal, the chromophore of visual pigments. We show here for zebrafish that embryonic retinoid homeostasis essentially depends on the activity of a leci-thin:retinol acyltransferase (Lratb). During embryogenesis, lratb is expressed in mostly non-overlapping domains opposite to retinal dehydrogenase 2 (raldh2), the key enzyme for retinoic acid synthesis. Blocking retinyl ester formation by a targeted knock down of Lratb results in significantly increased retinoic acid levels, which lead to severe embryonic patterning defects. Thus, we provide evidence that a balanced competition between Lratb and Raldh2 for yolk vitamin A defines embryonic compartments either for retinyl ester or retinoic acid synthesis. This homeostatic mechanism dynamically adjusts embryonic retinoic acid levels for gene regulation, concomitantly sequestering excess yolk vitamin A in the form of retinyl esters for the establishment of larval vision later during development.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyltransferases / genetics
  • Acyltransferases / metabolism
  • Aldehyde Oxidoreductases / genetics
  • Aldehyde Oxidoreductases / metabolism
  • Amino Acid Sequence
  • Animals
  • Cell Line
  • Drosophila
  • Egg Yolk / metabolism
  • Embryo, Nonmammalian / embryology
  • Embryo, Nonmammalian / metabolism
  • Esters / metabolism
  • Eye / embryology*
  • Eye / metabolism*
  • Gene Expression Regulation, Developmental
  • Homeostasis / physiology
  • Molecular Sequence Data
  • Retinaldehyde / metabolism
  • Retinoids / metabolism*
  • Signal Transduction / physiology*
  • Tretinoin / metabolism
  • Vitamin A / metabolism
  • Zebrafish / embryology*
  • Zebrafish / metabolism*

Substances

  • Esters
  • Retinoids
  • Vitamin A
  • Tretinoin
  • Aldehyde Oxidoreductases
  • Acyltransferases
  • lecithin-retinol acyltransferase
  • Retinaldehyde