Gen Yamada

The prechordal midline of the chondrocranium is defective in Goosecoid-1 mouse mutants

Gsc-1 expression marks cells with Spemann organizer, or axis-inducing, activity in the vertebrate gastrula. Gsc-1 knockouts, however, did not display phenotypes related to the early phase of expression. In this paper, additional phenotypes for the Gsc-1 mouse mutant are presented. Examination of the base of the cranium in the dorsal view revealed fusions and deletions in the midline of the prechordal chondrocranium. These defects were correlated with the sites of expression of Gsc-1 in the prechordal plate/foregut endoderm in the day 7.5/8.5 embryo. Gsc-1 expression in proximal limb buds was correlated with malformations of the shoulder and hip articulations. In addition, ribs in the seventh cervical vertebra were observed with low penetrance. The role of Gsc-1 during gastrulation and axial development is discussed in relation to possible compensatory interactions with other genes such as HNF-3beta and the recently identified Gsc-2 and Gsc-3 genes.

Malformation of Trachea and Pelvic Region in goosecoid Mutant Mice

The homeobox gene goosecoid is expressed in the Spemann organizer tissue of gastrulating vertebrate embryos, and in the craniofacial region and appendicular skeleton during organogenesis. The goosecoid knockout mutant mouse revealed defects related to the second phase of expression. Here we describe new expression sites in the developing trachea and external genitalia, and in the developing shoulder and hip joint with their associated ligaments and muscles. We show that mutant mice display abnormalities in the forming trachea and appendicular skeleton related to these sites of gene expression. In addition, we discuss evidence for the existence of at least three goosecoid genes in vertebrates, which may account for the lack of a defect of axial patterning in goosecoid mutant mice. Dev. Dyn. 1998;211:374–381.

Different element ratios of red cosmetics excavated from ancient burials of Japan

Marker elements of red cosmetics, collected from ancient burials of Matsuyama, Tokushima and Nara Japan, were determined by emission spectrometry (ICP/AES). The mass ratios of Hg, Fe, Cu, and Zn were different between samples. Element levels were compared with reference to relative amounts of sulfur. Of the possible contaminants from the bone and sand of burials, the relative amounts of Hg and Fe to S were most commonly available to evaluate the difference between the cosmetics. The cosmetics were divided into four groups; type I (high Hg with less Fe), type II (both moderate Hg and Fe), type III (moderate Hg with high Fe) and type IV (less Hg with high Fe). The main constituents of cosmetics are mercury sulfide (cinnabar) or ferric oxide mixed with trace metals. Zinc contents differ between the Fe and Hg amounts for the three areas. Cosmetic compositions varied with each burial site, suggesting that they were derived from different mines of ancient Japan.

Diversified Sex Characteristics Developments in Teleost Fishes: Implication for Evolution of Androgen Receptor (AR) Gene Function

Gene duplication is a dominant driving force of evolution. The steroid hormone receptor (SR) gene family is thought to have arisen from gene duplication. However, the molecular events which produce new protein functions after genome duplication have not been fully understood. Teleost fishes present an excellent model to investigate an accurate evolutionary history of protein function after whole genome duplication (WGD), because the teleost-specific WGD (TSGD) 350 million years ago (Ma) resulted in a variety of duplicated genes that exist in modern fishes. We focused on the androgen receptor (AR) gene, since two different subtype genes, ARα and ARβ, were generated in the TSGD. It was previously shown that ARβ has retained the ancestral function, whereas ARα has evolved as a hyperactive form of AR in the teleost lineage. Such evolutionary novelty of protein function in AR genes might facilitate the emergence of divergent sex characteristics in the teleost lineage. Results of the combined functional and 3D analyses of medaka ARs identified the substitutions that led to changes in protein structure and function between medaka ARα and ARβ. By tracing evolutionary changes in protein function of ARs in teleost lineage, we recently revealed that the substitutions generating a new functionality of teleost ARα were fixed in the teleost genome after the divergence of the Elopomorpha lineage. Such findings would provide an historical explanation for the retention of the duplicated AR copies in the euteleost genome. We also highlighted the molecular mechanisms of secondary sex characteristics development in teleost fishes, using Western mosquitofish and medaka as models.