N Osumi-Yamashita

Learn More
This study investigates the migration patterns of cranial neural crest cells in retinoic acid (RA)-treated rat embryos using DiI labeling. Wistar-Imamichi rat embryos were treated at the early (9.0 days post coitum, d.p.c.) and late (9.5 d.p.c.) neural plate stages with all-trans RA (2 x 10(-7) M) for 6 hours and further cultured in an RA-free medium. RA(More)
Craniofacial development of vertebrates depends largely on neural crest contribution and each subdomain of the crest-derived ectomesenchyme follows its specific genetic control. The rat small eye (rSey) involves a mutation in the Pax-6 gene and the external feature of rSey homozygous embryos exhibits craniofacial defects in ocular and frontonasal regions.(More)
Migration of cranial neural crest cells is a crucial event in the formation of facial organs such as the frontonasal mass and branchial arches. However, the source of the populating crest cells that occupy the frontonasal mass remains unclear in mammalian embryos. To elucidate this, we performed focal DiI injections at various sites in the prosencephalon(More)
A new mutant rat with small eyes (rSey) which was found in the course of breeding Sprague-Dawley rats is described. Genetic analysis demonstrates that rSey is inherited as an autosomal dominant mutation. Heterozygotes (rSey/+) have small eyes, while homozygotes (rSey/rSey) do not develop lens and nasal placodes, resulting in lack of eyes and the nose and(More)
Our review demonstrates that the whole embryo culture system established by New and his colleagues, in combination with beneficial fluorescent dye cell-tracing techniques, has greatly contributed to many advancements in the field of mammalian craniofacial embryology, especially with regard to elucidating the developmental behavior of cephalic crest cells.(More)
Teeth are formed by reciprocal interactions between the epithelium and mesenchyme in the first pharyngeal arch. Although the contribution of midbrain and hindbrain crest cells to the first pharyngeal arch has been previously examined in rodent embryos, no direct evidence exists that these cells are actually involved in the dental mesenchyme. In order to(More)
The rat small eye strain (rSey) lacks eyes and nose in the homozygote, and is similar to the mouse Sey strain with mutations in the Pax-6 gene. We isolated Pax-6 cDNA clones from an rSey homozygote library, and found an internal deletion of about 600 basepairs in the serine/threonine-rich domain. At the genomic level, a single base (G) insertion in an exon(More)
We have investigated the localization pattern of the transforming growth factor-beta (TGF-beta) receptors type I (T beta R-I) and type II (T beta R-II) during mouse organogenesis by immunohistochemical analysis. Staining of both receptors was found in many developing organs, e.g., bone, teeth, Meckel's cartilage, and neural tissues, where the expression of(More)
Neural crest (NC) is a transient structure that gives rise to various types of tissues. Many NC cells are pluripotent in the sense that their progeny can generate more than one derivative. However, the potentiality to differentiate into certain derivatives, such as cartilage and bone, seems to be specified with respect to the neuraxial levels at which the(More)
Retinoic acid (RA) is known as a teratogen that induces abnormalities in facial structures which are made up mainly of neural crest-derived mesenchyme. We investigated expression patterns of RA receptor (RAR) genes (subtypes alpha, beta, gamma) during mouse facial development. The expression of the RAR beta gene is specific for the mesenchyme around(More)