Contacting the matrix

In 1975, the extracellular matrix (ECM) and its potential as the “embryonic inducer” was just getting interesting, recalls Elizabeth Hay (Harvard Medical School, Boston, MA). Using an ingenious combination of biochemistry and tissue culture on the new Nucleopore filters, she and Stephen Meier would show that direct contact with the ECM was necessary for corneal epithelium to differentiate (Meier and Hay, 1975).

As early as 1955, Clifford Grobstein had proposed that the way one tissue induced another to develop might be through the presence of ECM (Grobstein, 1955). With his Millipore filter experiments he had shown that ECM alone could induce mouse salivary gland tissue to differentiate (Grobstein, 1953). A 1966 study showed that myoblasts plated onto collagen (then the known major component of ECM) would differentiate...