The International Journal of Developmental Biology

Int. J. Dev. Biol. 54: 135 - 140 (2010)

Vol 54, Issue 1

Over-expression of thymosin beta4 promotes abnormal tooth development and stimulation of hair growth

Original Article | Published: 25 November 2009

Hee-Jae Cha*,1, Deborah Philp2, Soo-Hyun Lee3, Hye-Sung Moon4, Hynda K. Kleinman2 and Takashi Nakamura2

1Department of Parasitology and Genetics, College of Medicine, Kosin University, Busan, S. Korea, 2Craniofacial Developmental Biology and Regeneration Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA, 3Department of Pharmaceutics, College of Pharmacy, Seoul National University, Seoul, S. Korea and 4Department of Obstetrics and Gynecology, School of Medicine, EWHA Womans University, Seoul, S. Korea


Thymosin beta4 has multi-functional roles in cell physiology. It accelerates wound healing, hair growth and angiogenesis, and increases laminin-5 expression in corneal epithelium. Furthermore, thymosin beta4 stimulates tumor growth and metastasis by induction of cell migration and vascular endothelial growth factor-mediated angiogenesis. Using a construct on the skin-specific keratin-5 promoter, we have developed thymosin beta4 over-expressing transgenic mice to further study its functional roles. Thymosin beta4 in adult skin and in embryonic stages of the transgenic mouse was analyzed by both Western blot and immunohistochemistry. The over-expression of thymosin beta4 was observed especially around hair follicles and in the teeth in the transgenic mice. We examined the phenotype of the thymosin beta4 over-expressing mice. Hair growth was accelerated. In addition, the transgenic mice had abnormally-shaped white teeth and dull incisors. We found that the expression of laminin-5 was up-regulated in the skin of the transgenic mice. We conclude that thymosin beta4 has an important physiological role in hair growth and in tooth development.


thymosin beta4, transgenic mice, hair growth, tooth development, laminin-5

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