A novel RNA affecting embryonic gene functions in early chick glastoderm

A low molecular weight RNA species (CEH-RNA Fraction 1a) of about 7 S size was isolated from the 16-day-old chick embryonic heart. The RNA was capable of inducing a specific mode of changes in the early embryonic cells of Stage 4 (definitive primative streak stage) chick blastoderm cultivated in vitro. These changes were similar to those of embryonic heart differentiation. RNAs from other sources isolated under identical conditions and synthetic polynucleotides were not effective. In the absence of inducer CEH-RNA, the embryonic cells remained undifferentiated. The dependence of heart-like differentiation on a specific RNA species thus offers an opportunity to test the gene-regulating role of the RNA in an experimentally analyzable biological system.