IN-SITU HYBRIDIZATION STUDY OF CYTOKERATIN-4, CYTOKERATIN-13, CYTOKERATIN-16 AND CYTOKERATIN-19 MESSENGER-RNAS IN HUMAN DEVELOPING JUNCTIONAL EPITHELIUM
M. Feghaliassaly et al., IN-SITU HYBRIDIZATION STUDY OF CYTOKERATIN-4, CYTOKERATIN-13, CYTOKERATIN-16 AND CYTOKERATIN-19 MESSENGER-RNAS IN HUMAN DEVELOPING JUNCTIONAL EPITHELIUM, European journal of oral sciences, 105(6), 1997, pp. 599-608
Cytokeratins (CKs) are now considered to be reliable markers for follo
wing the development and differentiation of epithelial tissue. We have
investigated the pathway of differentiation in human developing junct
ional epithelium using monoclonal antibodies and two-dimensional gel e
lectrophoresis of microdissected tissue to identify CK 19, CK 16, CK 1
4, CK 13, CK 6, CK 5, CK 4 in the junctional epithelium (JE) over part
ially erupted human teeth. The CK profile was similar to that of devel
oping oral epithelia, suggesting that the junctional epithelium in tee
th during eruption is of odontogenic origin. The present study used in
situ hybridization to determine the distribution of the mRNAs of CKs
19, 16, 13 and 4 in human developing junctional epithelium and to exam
ine the correlation between mRNAs and their encoded proteins. CK 19 mR
NA was abundant in the basal cell layers of the primary junctional epi
thelium (PJE) but less concentrated in the suprabasal layers. CK16, 13
and 4 mRNAs were abundant in the basal cell layers of the PJE. The pa
rabasal cell layers reacted intensely to the cRNA probe complementary
to CK16 mRNA, as were the reactions in the suprabasal cell layers of t
he PJE for the CK 13 and 4 probes. Our results demonstrate that the PJ
E express the genes encoding far CKs 16 and 4 that have been revealed
previously only by electrophoresis. They therefore confirm that the PJ
E is a well-differentiated stratified epithelium with a complex unique
phenotype that produces CKs specific for basal cells (CK 19), CKs ass
ociated with hyperproliferation (CK 16), and finally those associated
with stratification (CKs 4 and 13). Only synthesis of CK 19 protein an
d mRNA are strictly parallel. CKs 4 and 13 mRNAs are present in basal
and suprasal cells, while their encoded proteins were not, except for
CK 13 in suprabasal cell layers of PJE, where the amount of its mRNAs
was coincident with the expression of the protein.