Helder M N, Karg H, Bervoets T J, Vukicevic S, Burger E H, D'Souza R N, Wöltgens J H, Karsenty G, Bronckers A L
Department of Oral Cell Biology, ACTA, Vrije Universiteit, Amsterdam, The Netherlands.
J Dent Res. 1998 Apr;77(4):545-54. doi: 10.1177/00220345980770040701.
Bone morphogenetic proteins (BMPs) form a family of growth factors originally isolated from extracellular bone matrix that are capable of inducing bone formation ectopically. We studied the expression, tissue localization, and function of BMP-7 (OP-1) during tooth development in rodents. Patterns of BMP-7 gene expression and peptide distribution indicated that BMP-7 was present in dental epithelium during the dental lamina, bud, and cap stages. During the bell stage, BMP-7 mRNA expression and protein distribution shifted from dental epithelium toward the dental mesenchyme. With advancing differentiation of odontoblasts, BMP-7 protein staining in the dental papilla became restricted to the layer of fully functional odontoblasts in the process of depositing (pre)dentin. Secretory-stage ameloblasts exhibited weak immunostaining for BMP-7. A restricted pattern of staining in ameloblasts became apparent in post-secretory stages of amelogenesis. Also, cells of the forming periodontal ligament were immunopositive. Histological analysis of tooth development in neonatal BMP-7-deficient mice did not reveal obvious changes compared with wild-type mice. We conclude that, in developing dental tissues, BMP-7 has distribution and expression patterns similar to those of other BMP members but is not an essential growth factor for tooth development, possibly because of functional redundancy with other BMP members or related growth factors.
骨形态发生蛋白（BMPs）构成了一类最初从细胞外骨基质中分离出来的生长因子家族，它们能够在异位诱导骨形成。我们研究了BMP-7（OP-1）在啮齿动物牙齿发育过程中的表达、组织定位和功能。BMP-7基因表达和肽分布模式表明，在牙板、芽和帽状期，BMP-7存在于牙上皮中。在钟状期，BMP-7 mRNA表达和蛋白质分布从牙上皮向牙间充质转移。随着成牙本质细胞分化的推进，牙乳头中BMP-7蛋白染色局限于正在沉积（前期）牙本质的完全功能性成牙本质细胞层。分泌期成釉细胞对BMP-7表现出弱阳性免疫染色。在釉质形成的分泌后期，成釉细胞中出现了局限的染色模式。此外，正在形成的牙周膜细胞呈免疫阳性。与野生型小鼠相比，新生BMP-7缺陷小鼠牙齿发育的组织学分析未发现明显变化。我们得出结论，在发育中的牙齿组织中，BMP-7具有与其他BMP成员相似的分布和表达模式，但不是牙齿发育所必需的生长因子，这可能是由于与其他BMP成员或相关生长因子存在功能冗余。
