“ECM”: Its nature, origin and function in cell aggregation

Abstract

Evidence is presented to show that a viscous material referred to elsewhere as “ECM”, reportedly elaborated in vitro by aggregating embryonic cells and suggested to possess a variety of functions in the processes of cell aggregation and tissue reconstruction, is in reality a highly hydrated deoxyribonucleoprotein gel. The gel appears to be formed by the chromosomes of ruptured cells as a result of the enzymatic removal of a portion of the chromosomal protein by the trypsin employed for tissue dissociation. It originates in greatest part, in the material studied, from the broken cells at the cut surfaces of the tissue fragments, and it appears to form complexes with a variety of macromolecular materials present in cell suspensions or culture media. Cells aggregate normally in its total absence, by processes, it is assumed, involving intimate contact of the cell surfaces themselves. The possible role of cell products in promoting cell aggregation in vitro is discussed.