Year: 2004
Type: dissertation
Abstract: Two dominant mouse skin mutants, Recombinant-induced mutation 3 (Rim3) and Rex denuded (Reden), arose spontaneously in different inbred strains, but exhibit very similar phenotype of hyperkeratosis and alopecia. Both mutants have a genetic alteration in GasderminA-3 (GsdmA-3), which is a member of novel gene family, Gsdm. The Gsdm family commonly share unique leucine-rich C-terminus domain, but the functions of GsdmA-3 and Gsdm family are largely unknown. In this study, to elucidate the function of GsdmA-3 in the epidermal morphogenesis, I conducted analysis of spatiotemporal expression patterns of GsdmA-3 and the related genes. In addition, I carried out in-depth characterization of the Rim3 phenotype. The results indicated that GsdmA-3 is specifically expressed in differentiated keratinocytes in epidermis after postnatal stage, but not in proliferating epidermal cells. Immunohistochemical analysis of BrdU-labeled epidermis revealed hyperproliferation and misdifferentiation of the upper follicular cells and the epidermis in the Rim3 mutant. All the results suggested that GsdmA-3 is involved in downregulation of cellproliferation and differentiation of the epidermal stem cells. As collaboration with a research group of National Cancer Institute, Tokyo, it was demonstrated that a human homologue GSDMA has a tumor suppressor activity. Mice heterozygous for Trp53 knockout (Trp53-) allele are known to frequently develop lymphomas, but never develop skin tumors. Although mice heterozygous for the Rim3 mutation alone develop no skin tumors, I examined whether GsdmA-3 is involved in tumor suppression in the Trp53- genetic background. To do this, I generated mice heterozygous for both of the Rim3 and Trp53- alleles. As a result, the double heterozygous mice (GsdmA-3Rim3/+; Trp53+/+) developed multiple metastatic squamous cell carcinomas (SCC) as early as 7 months of the age. In conjunction with the data that a human homologue GSDMA is a tumor suppressor for gastric cancer in human, this result suggested that GsdmA-3 has a function to prevent tumor development in the mouse skin as well.
Authors: 成和 田中, シゲカズ タナカ, Shigekazu Tanaka
Language: English
Topic: Hair Growth and Disorders
Subfield: Dermatology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W139379261