Nature 295, 434 - 436 (04 February 1982); doi:10.1038/295434a0

Stratification and terminal differentiation of cultured epidermal cells

Fiona M. Watt^*‡ & Howard Green^*†

^*Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
^†Department of Physiology and Biophysics, Harvard Medical School, Boston, Massachusetts 02115, USA
^‡Present address: Kennedy Institute of Rheumatology, Hammersmith, London W6 7DW, UK.

As keratinocytes move from the basal to the outer layers of a stratified squamous epithelium, they enlarge and terminally differentiate. Hence, the stage of terminal differentiation is correlated with both cell size and position. To determine whether position is an important signal in differentiation, we have now grown human keratinocytes in conditions that prevented stratification but not cell enlargement. Involucrin, a marker of terminal differentiation, was synthesized in such a monolayer, but only by large cells. We conclude that the onset of involucrin synthesis, while normally restricted to cells in a non-basal position, does not depend on this position for an essential signal; however, a signal associated with increased cell size is not ruled out. When monolayer cultures were induced to stratify, the large involucrin-containing cells preferentially adopted a suprabasal position, indicating that terminal differentiation is associated with a decrease in substrate adhesiveness. Suprabasal cell position is therefore a consequence rather than a cause of terminal differentiation.

References

1.	Rice, R. H. & Green, H. Cell 18, 681−694 (1979). | Article | PubMed | ISI | ChemPort |
2.	Banks-Schlegel, S. & Green, H. J. Cell Biol. 90, 732−737 (1981). | Article | PubMed | ChemPort |
3.	Watt, F. M. & Green, H. J. Cell Biol. 90, 738−742 (1981). | Article | PubMed | ISI | ChemPort |
4.	Hennings, H. et al. Cell 19, 245−254 (1980). | Article | PubMed | ISI | ChemPort |
5.	Iversen, O. H., Bjerknes, R. & Devik, F. Cell Tissue Kinet. 1, 351−367 (1968).
6.	Steinberg, M. Proc. natn. Acad. Sci. U.S.A. 48, 1769−1776 (1962).
7.	Moscona, A. Expl Cell Res. 22, 455−475 (1961). | ChemPort |
8.	Doran, T. I., Vidrich, A. & Sun, T.-T. Cell 22, 17−25 (1980). | Article | PubMed | ISI | ChemPort |
9.	Rheinwald, J. G. & Green, H. Cell 6, 317−330 (1975). | Article | PubMed | ISI | ChemPort |
10.	Green, H. Cell 15, 801−811 (1978). | Article | PubMed | ISI | ChemPort |
11.	Rheinwald, J. G. & Green, H. Nature 265, 421−424 (1977). | PubMed | ISI | ChemPort |
12.	Brennan, J. K., Mansky, J., Roberts, G. & Lichtman, M. A. In Vitro 11, 354−360 (1975). | PubMed | ISI | ChemPort |
13.	Green, H., Kehinde, O. & Thomas, J. Proc. natn. Acad. Sci. U.S.A. 76, 5665−5668 (1979). | ChemPort |