Domains of cellular retinoic acid-binding protein I (CRABP I) expression in the hindbrain and neural crest of the mouse embryo

Retinoic acid (RA) has been implicated in vertebrate neural pattern formation. In this paper we analysed the expression patterns of the cellular retinoic acid binding proteins (CRABP‐I and II) during early morphogenesis in normal and RA‐treated mouse embryos by whole‐mount in situ hybridization. This technique allowed a detailed analysis of the spatial and temporal changes in mRNA expression pattern. Both CRABPs were expressed in a rhombomere specific pattern; putative neural crest cells in the branchial arches expressed the CRABPs at levels corresponding to the rhombomere from which they were derived. CRABP‐II, but not CRABP‐I, was expressed in the neural epithelium caudal to the hindbrain. CRABP‐I is strongly expressed in a fine net‐like pattern which extends from the caudal diencephalon to the rostral hindbrain and remains predominantly dorsal to the lateral midline of the neural tube. This network corresponds to the pattern formed by the putative first axons of the embryonic mouse brain which are produced by the developing neurons of the mesencephalic nucleus of the trigeminal nerve. Although the expression of CRABP‐I was unaffected by a teratogenic dose of RA, CRABP‐II expression was increased slightly with no alteration in the normal spatial or temporal boundaries. These results support the suggestion that the CRABPs may play an important role in modulating endogenous RA levels, particularly in the developing nervous system and its neural crest derivatives. Furthermore, the limited ability of CRABP mRNA levels to respond to exogenous retinoids may be a factor in retinoid teratogenicity. © 1994 Wiley‐Liss, Inc.

Section: Whole-mount In Situ Hybridization Analysissupporting

confidence: 93%

Section: Discussionsupporting

confidence: 66%

Localization of CRABP‐I and CRABP‐II mRNA in the early mouse embryo by whole‐mount in situ hybridization: Implications for teratogenesis and neural development

Lyn

Giguère

1994

“…Furthermore, when this superficial correlation is examined in more detail it too breaks down. Thus we only observed abnormalities in branchial arch 1, yet this is the arch with the lowest level of CRABP (Maden et al, 1992). The other arches express high levels of CRABP, but were not apparently affected.…”

Section: Teratogenesis Vs Presence Of Crabp I and Crabp I1mentioning

confidence: 53%

“…CRABP I protein was also localised in wax sections of untreated day 10.5 embryos using a polyclonal antibody raised to a sequence of bovine CRABP I by the method previously described in Maden et al (1992). The specificity of this antibody is also discussed in this work.…”

Section: Localisation Of Crabp I and Crabp I1mentioning

confidence: 94%

Endogenous distribution of retinoids during normal development and teratogenesis in the mouse embryo

Horton

Maden

1995

Self Cite

220

140

We have analysed the endogenous retinoids present in whole mouse embryos from day 9 to day 14 of development and in individual components of the embryo at two stages, day 10.5 and day 13, by HPLC. We can only detect two retinoids, all-trans-RA (tRA) and all-transretinol (t-retinol), and t-retinol is 510-fold in excess over tRA. We cannot detect 9-cis-RA or any didehydroretinoids; thus mammalian embryos seem to differ in their retinoid content from other embryos such as chick, Xenopus, and fish. The levels of tRA do not change significantly over the 6 days of development analysed, whereas t-retinol rises sharply as the liver develops. Within the embryo, tRA is present at high levels in the developing spinal cord and at very low levels in the forebrain; indeed there is a gradient of endogenous tRA from the forebrain to the spinal cord. Other parts of the embryo had intermediate levels of tRA. When a teratogenic dose of RA was administered to day 10.5 embryos, the levels of tRA present in individual tissues of the embryo rose dramatically-from 175-fold to 1,400-fold-and the levels rose in all tissues not in any exclusive areas. We then determined which areas of the embryo were malformed by such a teratogenic dose. The lower jaw, palate, vertebrae, tail, and limbs were consistently abnormal, and since these areas received a dose of tRA no higher than any other it was concluded that cell-specific factors must determine the teratogenic response of these tissues. We then considered whether cellular retinoic acid-binding protein I or I1 (CRABP I or 11) played any role in this response by determining their relative levels in each of the tissues analysed. There was no correlation between the presence of CRABP I and 11 and the distribution of administered RA. Neither was there a clear correlation in detail between the presence of CRABP I and I1 and the sites of teratogenesis. We therefore conclude that other factors, for example, nuclear factors, must be responsible for the teratogenic response to RA. o 1995 Wiley-Liss, Inc.

“…The in situ hybridization signal is shown in false colors after computer processing of a bright-field view (showing the histology) and a dark-field view (revealing the autoradiography silver grain signal) of the same section. The threshold levels for false colors have been selected in order to eliminate the isolated (background) silver grains, but to reveal all significant labelling (yellow) as well as more intensely labelled areas differences in intracellular RA levels (Doll6 et al, 1989(Doll6 et al, ,1990(Doll6 et al, ,1994Ruberte et al, 1990Ruberte et al, ,1991Vaessen et al, 1990;Maden et al, 1992;Dencker et al, 1990;Mangelsdorf et al, 1992). A comprehensive understanding of RA function during development cannot be reached without determining in which cells this ligand is actually produced.…”

mentioning

confidence: 99%

Stage and tissue‐specific expression of the alcohol dehydrogenase 1 (Adh‐1) gene during mouse development

Vonesch

Nakshatri

Philippe

et al. 1994

The Adh-1 gene product, ADH-A2, the only known murine class I alcohol dehydrogenase, is able to oxidize retinol (vitamin A) into retinaldehyde, the first enzymatic step in the conversion of retinol into its biologically active metabolite retinoic acid. We have investigated the developmental expression pattern of Adh-1 transcripts by in situ hybridization. Transcripts were first detected by embryonic day 10.5 in the mesonephros mesenchyme. During the following gestational days, Adh-1 transcripts were detected in several mesenchymal areas, such as nasal, laterocervical, and genital regions. Adh-1 transcripts were also detected in a small ectodermal domain at the anterior margins of both forelimbs and hindlimbs. During late fetal development, Adh-1 transcripts were found essentially in the epidermis and in a number of tissues which continue to express the gene after birth, such as liver, kidney, gut epithelium, adrenal cortex, testis interstitium, and ovarian stroma. In contrast, a strong expression of Adh-1 was found in the mesenchyme of developing lungs, but not in the adult organ. This highly regulated expression of Adh-1 is discussed with respect to the local synthesis of retinoic acid during development. Although the promoter of the human counterpart of Adh-1 contains a retinoic acid response element (Duester et al. 119913 Mol. Cell. Biol. 11:1638-1646), we report that this element is not conserved in the murine gene. Consistently, Adh-1 promoter-containing reporter constructs were not retinoic acid-inducible in cotransfections assays with RARs and/or RXRs, suggesting that retinoic acid regulation of Adh-1 differs from that of the human gene.