From Science News Letter, September 13, 1958

RNA INFLUENCES CELL DIFFERENTIATION — Ribonucleic acid has been pinpointed as having an essential role in cell differentiation, the process by which the early embryo’s look-alike cells become nerve, bone, skin and other organs. Working with extremely small quantities of cellular material, 20 to 50 cells, taken from embryonic newt and salamander tissue, Dr. M. C. Niu of the Rockefeller 
Institute for Medical Research, New York, found that the presence of ribonucleic acid is critical for the formation of specialized tissues. He used cells removed from two-to-five-day-old fertilized eggs that under ordinary circumstances would become epithelial or skin tissue. These cells, Dr. Niu told Science Service, have the unique characteristic of multi-potentiality.… By growing the cells in a hanging drop of saline solution that included a 97% pure extract of nucleic acid and protein taken from cow tissue, Dr. Niu was able to control cell differentiation.