APin expression during amelogenesis

Abstract

이 연구에서는 흰쥐 절치의 법랑모세포 분과과정 중에 전에 흰쥐 상아모세포에서부터 분리된 APin의 발현을 in situ hybridization과 면역조직화학적방법 이용하여 연구하여 다음과 같은 결과를 얻었다. APin의 세포내 발현(subcellular localization)은 법랑모세포 분화과정 중에 다양하게 나타났다. APin mRNA는 법랑모세포전구세포(preameloblasts)에서는 발현이 되지 않았고, 분비기 법랑모세포(secretory ameloblasts)에서는 약하게 발현되었으며, 구치의 법랑질에 부착된 부착상피(junctional epithelium) 뿐 아니라 성숙기의 법랑모세포(maturation stage ameloblasts)에서 강하게 발현되었다. 성숙기 법랑모세포에서 APin 단백질은 ruffle-ended 법랑모세포의 supranuclear area와 ruffle end 뿐 아니라 smooth-ended 법랑모세포의 supranuclear area (Golgi complex)에서 강하게 발현되었다. 법랑모세포주(ACL) 배양 동안에 APin의 발현은 배양 초기에는 약하였으나 성숙기에 해당되는 배양의 말기에는 강하게 발현되었다. APin 단백질은 배양한 transfected cell로부터 효과적으로 분비되었으며, 더더욱 그의 과발현은 matrix metalloproteinase-20과 tuftelin의 발현을 증가시겼고, 발현억제는 이들의 발현을 감소시켰다. 위의 결과들은 MMP-20과 tuftelin의 발현에 의해 조절되는 법랑질의 석회화와 성숙에 있어서 APin의 기능적 역할을 암시한다.|This investigated the expression and localization of APin cDNA, which was previously identified and cloned from a rat odontoblast cDNA library, during ameloblast differentiation in rat incisors using in situ hybridization and immunohistochemistry. The subcellular localization of APin varied during ameloblast differentiation but was stage-specific. APin mRNA was not expressed in the preameloblasts, was weakly expressed in the secretory ameloblasts and strongly expressed in the maturation stage ameloblasts as well as in the junctional epithelium attached to the enamel of molars. In the maturation stage ameloblasts, APin protein was strongly expressed in the supranuclear area (Golgi complex) of the smooth-ended ameloblasts as well as in both the supranuclear area and the ruffle end of the ruffle-ended ameloblasts. During the ameloblast-lineage cell culture, APin was expressed at a low level in the early stages, but at a high level in the late stage of culture, which was equivalent to the maturation stage. APin protein was efficiently secreted from transfected cells in culture. Furthermore, its over-expression and inactivation caused an increase and decrease in matrix metalloproteinase-20 (MMP-20) and tuftelin expression, respectively. These findings indicate a functional role for APin in the mineralization and maturation of the enamel that is mediated by the expression of MMP-20 and tuftelin.