title: Changes of the expression and distribution of retinoic acid receptors during neurogenesis in mouse embryos.
abstract: The expression and distribution of three retinoic acid receptors, alpha, beta, and gamma, were investigated in the CNS of mouse embryos during development. mRNAs and protein of RAR-beta that were expressed in the spinal cord of the 12.5-day mouse embryo decreased during development but they were not decreased in the brain. The RAR-beta-positive cells were already present in the ventral region of the spinal cord of 10.5-day mouse embryos, gradually appeared in the dorsal region during development and then disappeared from the spinal cord after birth. In the brain, RAR-beta-positive cells were detected in the mesencephalon and rhombencephalon but not in the telencephalon of the 12.5-day mouse embryos. RAR-beta-positive cells were present in the hippocampus and cingulum but not in the neocortex of 14.5-day mouse embryos. Most neurons in the hippocampus of 16.5-day mouse embryos and the cortex of newborn mice were RAR-beta-positive. In the spinal cord, RAR-alpha mRNAs and proteins also decreased during development but more gradually than RAR-beta mRNAs and proteins. During development, the distributions of RAR-alpha and -beta in the spinal cord and brain did not differ substantially. The main difference was the appearance of a subtypes of RAR-alpha, a 52-kDa protein, in the brain of newborn mice. On the other hand, RAR-gamma proteins were only faintly detected in the spinal cord and the brain of the mice during the embryonal stages but these increased after birth. The distribution of RAR-alpha- or -beta-positive cells were consistent with the neurogenesis during development in the spinal cord and brain.
authors.affiliation: Department of Pediatrics, Jichi Medical School, Tochigi, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yamagata
authors.forename: M Y
authors.initials: MY
authors.lastname: Momoi
authors.forename: M
authors.initials: M
authors.lastname: Yanagisawa
authors.forename: H
authors.initials: H
authors.lastname: Kumagai
authors.forename: M
authors.initials: M
authors.lastname: Yamakado
authors.forename: T
authors.initials: T
authors.lastname: Momoi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern; D001921:Brain / Q000196:embryology / Q000378:metabolism; D005260:Female; D015151:Immunoblotting; D007150:Immunohistochemistry; D051379:Mice; D008969:Molecular Sequence Data; D009420:Nervous System / Q000196:embryology* / Q000378:metabolism*; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis; D018168:Receptors, Retinoic Acid / Q000096:biosynthesis* / Q000378:metabolism; D013116:Spinal Cord / Q000196:embryology / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid