F. Beck et al., THE EXPRESSION OF THE GENE CODING FOR PARATHYROID HORMONE-RELATED PROTEIN (PTHRP) DURING TOOTH DEVELOPMENT IN THE RAT, Cell and tissue research, 280(2), 1995, pp. 283-290
By means of in situ hybridisation studies, it is shown that parathyroi
d hormone-related protein (PTHrP) mRNA is strongly expressed in the de
veloping enamel organs of rat teeth. In particular, the cervical loop
hybridises strongly with the PTHrP probe and expression is maintained
at this site throughout life in the permanently erupting incisor teeth
. In mature molar teeth, expression is downregulated to low levels and
confined to the epithelial cell rests of Malassez and/or cementoblast
s which may derive from these. The gene is also expressed at low level
s in the tissue overlying the erupting molars and, thereafter, in the
junctional epithelia and connective tissue cells of the epithelial att
achment on all tooth surfaces. The premise that PTHrP may undergo post
-translational processing and that the resultant products could act in
different ways raises the possibility of its exerting multiple paracr
ine actions during tooth development. These could include the control
of cell division and local vascular dilation during development.