Embryonic Serum Factors Required for Transdifferentiation of Chick Embryo Neuroretinal Cells in Culture |
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Authors: | D I DE POMERAI M A H GALI |
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Institution: | Department of Zoology, University of Nottingham, Nottingham, NG7 2RD, UK. |
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Abstract: | The accumulation of δ crystallin (chick lens marker) in cultures of 9 day chick embryo neuroretinal cells is strongly promoted by chick embryo extract (CEE) or foetal calf serum (FCS), but much less so by adult sera (horse, chicken and newborn bovine serum). The "transdifferentiation-promoting" (TP) activity of FCS is absent from dialysed FCS but is largely recovered in the initial dialysis medium (FDM). Similarly, the initial dialysis medium from CEE (EDM) shows strong TP activity, whereas that from chicken or from horse serum does not. We conclude that the proposed TP factor(s) is (are) of relatively low molecular weight. By contrast, horse serum contains macromolecular factor(s) able to inhibit the TP activity of EDM or FDM. Rapid loss of neuronal cells (including those expressing choline acetyltransferase activity) is also observed in media based on FDM, though whether this effect is mediated by the proposed TP factor(s) has not been determined. The TP activity is not directly related to growth rate or cell density, since cultures in FDM alone grow poorly yet still accumulate δ crystallin. |
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