Krajewski S, Hugger A, Krajewska M, Reed J C, Mai J K
The Burnham Institute* (formerly La Jolla Cancer Research Foundation), 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
Cell Death Differ. 1998 May;5(5):408-15. doi: 10.1038/sj.cdd.4400360.
The ontogenic profile of expression of four members of the Bcl-2 family (Bcl-2, Bcl-x, Bax and Bak) was examined in the mouse by immunohistochemistry using paraffin sections. All four members were expressed in changing patterns during critical stages of tooth morphogenesis. Expression was detected in epithelial cell populations including the dental lamina, internal dental epithelium (IDE; differentiating ameloblasts), stratum intermedium and stellate reticulum cells, as well as in the condensed dental mesenchyme. The temporo-spatial localization of the various members of the Bcl-2 family in dental epithelium and mesenchyme showed striking overlapping areas but often their expression patterns differed. In general, contemporaneous co-expression of the Bcl-2 and Bax proteins, and of the Bcl-x and Bak proteins was noted in various types of cells during the developmental process, with the intensity of Bcl-2>Bax and of Bak>Bcl-x. Expression was pronounced at sites where interaction between surface ectoderm and induced mesenchyme takes place, and at the enamel knot, which is regarded as organization/regulating center for tooth development. Around birth, after the structural maturation was accomplished, the expression was down-regulated. The absence of elevated expression of each of these four members of the Bcl-2 family after birth in the teeth suggests that these proteins are relevant during the accomplishment of the basic architecture but not once the structure of the tooth is established.
通过使用石蜡切片的免疫组织化学方法，在小鼠中检测了Bcl-2家族四个成员（Bcl-2、Bcl-x、Bax和Bak）的个体发育表达谱。在牙齿形态发生的关键阶段，所有四个成员均以变化的模式表达。在包括牙板、内釉上皮（IDE；分化中的成釉细胞）、中间层和星网状层细胞在内的上皮细胞群体以及凝聚的牙间充质中均检测到表达。Bcl-2家族各成员在牙上皮和牙间充质中的时空定位显示出明显的重叠区域，但它们的表达模式通常不同。一般来说，在发育过程中，在各种类型的细胞中均观察到Bcl-2和Bax蛋白以及Bcl-x和Bak蛋白同时共表达，且Bcl-2的表达强度大于Bax，Bak的表达强度大于Bcl-x。在表面外胚层与诱导的间充质发生相互作用的部位以及被视为牙齿发育的组织/调节中心的釉结处，表达明显。出生前后，在结构成熟完成后，表达下调。牙齿出生后这四个Bcl-2家族成员中每个成员均未出现表达升高，这表明这些蛋白质在基本结构形成过程中发挥作用，但在牙齿结构建立后则不再相关。
