Expression of retinoic acid 4-hydroxylase (CYP26) during mouse and Xenopus laevis embryogenesis

Mech Dev. 1999 Apr;82(1-2):205-11. doi: 10.1016/s0925-4773(99)00016-7.


Retinoids are important signal molecules during vertebrate embryonic development and their synthesis as well as catabolism should therefore be strictly regulated. The retinoic acid (RA) 4-hydroxylase, belonging to the cytochrome P450 family CYP26, is an enzyme catalyzing the 4-hydroxylation of RA, thereby regulating RA homeostasis. Here we describe the temporal and spatial expression patterns of mouse (mCYP26) and Xenopus laevis (xCYP26) homologues. In mouse, expression is detected in uterine crypt, around differentiating cartilage, several regions of the head, regions of the pharynx, the neural retina, and several regions of the trunk. In Xenopus, Northern blot analysis shows presence of xCYP26 transcripts before the MBT and an increased expression level during gastrulation. Whole-mount in situ hybridization shows a specific expression pattern arising at onset of gastrulation, with a ring around the blastopore. By mid gastrulation there is an anterior and a posterior expression domain, each of which gets more complex later in development. There are some important similarities and differences in expression pattern between Xenopus and mouse.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Cytochrome P-450 Enzyme System / genetics*
  • DNA Primers / genetics
  • Female
  • Gene Expression Regulation, Developmental / drug effects
  • Gene Expression Regulation, Enzymologic / drug effects
  • In Situ Hybridization
  • Mice
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Retinoic Acid 4-Hydroxylase
  • Species Specificity
  • Tissue Distribution
  • Tretinoin / pharmacology
  • Xenopus laevis / embryology*
  • Xenopus laevis / genetics*


  • DNA Primers
  • RNA, Messenger
  • Tretinoin
  • Cytochrome P-450 Enzyme System
  • Retinoic Acid 4-Hydroxylase