Increased neonatal mortality in mice lacking cellular retinol-binding protein II.
Cellular retinol-binding protein II (CRBP II) is a member of the cellular retinol-binding protein family, which is expressed primarily in the small intestine. To investigate the physiological role of CRBP II, the gene encoding CRBP II was inactivated. The saturable component of intestinal retinol uptake is impaired in CRBP II(-/-) mice. The knockout mice, while maintained on a vitamin A-enriched diet, have reduced (40%) hepatic vitamin A stores but grow and reproduce normally. However, reducing maternal dietary vitamin A to marginal levels during the latter half of gestation results in 100% mortality/litter within 24 h after birth in the CRBP II(-/-) line but no mortality in the wild type line. The neonatal mortality in heterozygote offspring of CRBP II(-/-) dams (79 +/- 21% deaths/litter) was increased as compared with the neonatal mortality in heterozygote offspring of wild type dams (29 +/- 25% deaths per litter, p < 0.05). Maternal CRBP II was localized by immunostaining in the placenta at 18 days postcoitum as well as in the small intestine. These studies suggest that both fetal as well as maternal CRBP II are required to ensure adequate delivery of vitamin A to the developing fetus when dietary vitamin A is limiting.
E
Xueping
X
Department of Medicine, Washington University, St. Louis School of Medicine, St. Louis, Missouri 63110, USA.
Zhang
Liang
L
Lu
Jianyun
J
Tso
Patrick
P
Blaner
William S
WS
Levin
Marc S
MS
Li
Ellen
E
D000818:Animals; D018076:DNA, Complementary / Q000378:metabolism; D005260:Female; D005822:Genetic Vectors; D006579:Heterozygote; D007150:Immunohistochemistry; D007421:Intestine, Small / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D008431:Maternal-Fetal Exchange; D051379:Mice; D018345:Mice, Knockout; D008957:Models, Genetic; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D011485:Protein Binding; D012313:RNA / Q000378:metabolism; D012176:Retinoids / Q000378:metabolism; D012177:Retinol-Binding Proteins / Q000235:genetics* / Q000502:physiology*; D054840:Retinol-Binding Proteins, Cellular; D013997:Time Factors; D014801:Vitamin A / Q000494:pharmacology
D018076:DNA, Complementary; C518460:Rbp2 protein, mouse; D012176:Retinoids; D012177:Retinol-Binding Proteins; D054840:Retinol-Binding Proteins, Cellular; D014801:Vitamin A; D012313:RNA