Hertwig's epithelial root sheath (HERS) consists of bilayered cells derived from the inner and outer dental epithelia and plays important roles in tooth root formation as well as in the maintenance and regeneration of periodontal tissues. With regards to the fate of HERS, and although previous reports have suggested that this entails the formation of epithelial rests of Malassez, apoptosis or an epithelialmesenchymal transformation (EMT), it is unclear what changes occur in the epithelial cells in this structure. This study examined whether HERS cells undergo EMT using a keratin-14 (K14) cre:ROSA 26 transgenic reporter mouse. The K14 transgene is expressed by many epithelial tissues, including the oral epithelium and the enamel organ. A distinct K14 expression pattern was found in the continuous HERS bi-layer and the epithelial diaphragm were visualized by detecting the β-galactosidase (lacZ) activity in 1 week postnatal mice. The 2 and 4 week old mice showed a fragmented HERS with cell aggregation along the root surface. However, some of the lacZ-positive dissociated cells along the root surface were not positive for pan-cytokeratin. These results suggest that the K14 transgene is a valuable marker of HERS. In addition, the current data suggest that some of the HERS cells may lose their epithelial properties after fragmentation and subsequently undergo EMT.

동양에서는 생약을 주로 한약조제에 많이 이용되고 있으나 서양에서는 신의약품 개발과 제조에 이용되고 있다. 그러나 최근에 와서는 국내외를 막론하고 제약업계에서 양약의 제조와 신의약품 개발에 치중하여 생약의 수요가 증가하고 있다. 따라서 당국에서는 계획생산에 대한 지도와 자금지원, 품종관리, 재배 및 신의약품개발에 대한 연구지원, 수입통제에 의한 농민보호등 제도적 지원을 강화하여 우리나라 주종 재배약초의 자포자기적인 생산기피현상을 막아야 할 것이다.