Are globin coding sequences expressed in nuclear RNA of chick embryo brain?

The content of globin coding sequences in nuclear RNA from chicken embryo red blood cells and chicken embryo brain was determined by hybridization with globin cDNA to be 0.27% for embryonic red blood cells and 0.001% for embryo brain, i.e. 0.37% of globin coding sequences relative to embryonic red blood cells. By transfusion of [3H]uridine labelled red blood cells it could be shown that the brain nuclear RNA preparation was contaminated by 0.41% RNA originating from blood cells. As this value is in the same range as the hybridization rate there is no evidence for globin transcripts in brain nuclear RNA. It has also not been possible to detect a short-lived globin mRNA precursor in pulse labelled brain nuclear RNA. In further experiments the RNAs were translated in an Ehrlich ascites cell-free system. No globin synthesis could be observed with brain RNA.