Precursors of globin mRNA in erythroid-enriched bone marrow cells of mouse

RNA from erythroid-enriched bone marrow cells of mouse was analyzed under two kinds of denaturing conditions (in 99% formamide and formaldehyde treatment), and globin mRNA sequence-containing RNAs larger than 18S in addition to 16S and 10S were detected by hybridization at a comparatively high Rot with complementary DNA (cDNA) to globin mRNA (10S). The existence of precursor RNAs larger than 18S was confirmed by two different methods; (i) recentrifugation in 99% formamide of RNA collected from the corresponding regions of RNA fractions and following detection of globin mRNA sequences, (ii) the specific isolation of [3H]labeled precursor RNA with a cDNA-cellulose column and fractionation in a 99% formamide-sucrose gradient. Furthermore, pulse-chase experiments indicated that some large RNAs with globin mRNA sequences could be chased to 10S RNA during a 30 min chase in the presence of a high concentration of actinomycin D (10 microgram/ml). From the results it was assumed that 35-37S RNAs with globin mRNA sequences were possible primary transcripts of globin genes and other RNAs with globin mRNA sequences in 16S, 20S, and 26S regions were intermediate precursors of 10S globin mRNA.