Khan Qalb-E-Saleem, Press Charles McL, Sehic Amer, Landin Maria A, Risnes Steinar, Osmundsen Harald
Department of Oral Biology, University of Oslo, Oslo, Norway.
Eur J Oral Sci. 2010 Dec;118(6):559-65. doi: 10.1111/j.1600-0722.2010.00783.x. Epub 2010 Oct 14.
In order to gain insight into possible cellular functions of the prion protein (PrP) during normal development, the expression of Prnp (encoding the PrP) and the distribution of the PrP were studied in murine tooth germs. Expression of Prnp in the mouse first molar tooth germ was highly dynamic, increasing several-fold during the secretory phase of odontogenesis, exhibiting a time-course of expression similar to that of genes coding for other extracellular proteins [e.g. enamel matrix proteins (Amelx, Ambn, Enam), Aplp1, Clstn1, and Clu]. Western blot analysis suggested that the amounts of PrP and amyloid beta (A4) precursor-like protein 1 (APLP1) in the tooth germ followed time-courses similar to those of the corresponding mRNAs. Immunohistochemical studies of the distribution of PrP in murine molar and incisor tooth germs at embryonic day (E)18.5 suggested that this protein was located in the cervical loop, outer enamel epithelium, pre-ameloblasts, and dental papilla. Different degrees of immunolabelling of pre-ameloblasts on the mesial and distal aspects of a lower molar cusp may be related to different enamel configurations on the two aspects. It is concluded that the dynamic patterns of expression of Prnp, and of distribution of PrP, suggest that PrP may have functions during secretory odontogenesis, perhaps in relation to amelogenesis.
为深入了解朊病毒蛋白（PrP）在正常发育过程中可能的细胞功能，研究了朊病毒蛋白基因（Prnp，编码PrP）在小鼠牙胚中的表达情况以及PrP的分布。Prnp在小鼠第一磨牙牙胚中的表达具有高度动态性，在牙本质形成的分泌期增加了数倍，其表达的时间进程与编码其他细胞外蛋白的基因（如釉质基质蛋白（Amelx、Ambn、Enam）、Aplp1、Clstn1和Clu）相似。蛋白质印迹分析表明，牙胚中PrP和淀粉样β（A4）前体样蛋白1（APLP1）的含量随时间变化的过程与相应mRNA相似。对胚胎第18.5天（E18.5）小鼠磨牙和切牙牙胚中PrP分布的免疫组织化学研究表明，该蛋白位于颈环、外釉上皮、成釉细胞前体和牙乳头中。下磨牙牙尖近中和远中侧成釉细胞前体不同程度的免疫标记可能与两侧不同的釉质结构有关。研究得出结论，Prnp表达的动态模式以及PrP的分布表明，PrP可能在分泌性牙本质形成过程中发挥作用，可能与釉质形成有关。
