Changes in the Frequency and Diversity of Messenger RNA Populations in the Course of Myogenic Differentiation

Complementary DNAs (cDNAs) were synthesized from polyadenylated RNAs of myoblasts and myotubes and used to analyze changes in the sequence complexity and frequency distribution of messenger RNAs during myogenesis in vitro. cDNA · polyadenylated‐RNA hybridization kinetics show the presence of messenger RNA sequences specific for myotubes in fully differentiated muscle cultures. These sequences are accumulated just prior to fusion, as was shown by hybridizations of myotube cDNA and total cytoplasmic RNAs from cells at different stages of differentiation. The myotube cDNA can be enriched 10‐fold in myotube‐specific RNA species by a hybridization with cytoplasmic RNAs from myoblasts and subsequent removal of these hybridized sequences by hydroxyapatite.