Our in vitro work shows that the redirection of cell fate from neural retina to lens and subsequent transdifferentiation is independent of cell replication as it occurs in growth-arrested cell populations. Hence, for lack of overt lens progenitors, and most importantly, for its mitotic independence, we conclude that lens colony formation in vitro does occur by direct transdifferentiation and not by clonal proliferation of progenitor cells . Next, they were fixed, permeabilized and labelled with propidium iodide. To mark cells of interest you may want to use a green-fluorescent label. This can be related to the number of cell divisions in culture.
Standard precautions regarding image acquisition apply.