THE INDUCTIVE CAPACITY OF PROTEINS SECRETED BY CELLS OF CORNEAL EPITHELIUM
V. N. Zemchikhina,1 E. V. Gibalkina
Institute of Gene Biology, RAS, Moscow, Russia
1 e-mail: vellbiogen@mail.ru
Two classes of proteins play a leading role in the mechanisms of differentiation. The first class presents structural
proteins that are fundamental for the structure and function of organs. Proteins of the second class are less understood; they exist in
minor quantities and realize their action only in determining the accomplishment by structural proteins of their terminal functional
state. Here we try to clarify the role of peptides synthesized by the corneal epithelium in determining the fate of differentiating
cells. The acting protein fractions were obtained from isolated corneas of adult pigs, cows and carps. Their inducing activities were
tested by a standard method, i. e. by checking their action on the early gastrula ectoderm of Xenopus laevis. To study a possibility of
cornea conservation, we used preferentially lyophilizing drying of the obtained substances. With some differences in frequency, the
protein mixtures obtained from all corneas induced the appearance of neural tissue (brain), but in the case of lyophilized cow corneas
lenses, ear vesicles and somites also appeared. The results of this work clearly show the absence of homology between the sources of
inducing factors and the specificity of their action. The cornea is an ectodermal derivative, but its products induce neural derivatives
and, moreover, after lyophili-zation they change their induction specificity and induce also mesodermal cell types due, presumably, to
changes in the tertiary structure of protein molecules after lyophilization.
Key words: corneal epithelium, induction, early gastrula ectoderm, Xenopus laevis, Rana temporaria
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