Some unusual properties of globin-mRNA isolated from rabbit reticulocytes

Globin mRNA isolated from rabbit reticulocytes showed an unusually high molecular weight for the beta-chain mRNA (280000 daltons), a large difference between the molecular weight of the alpha-chain mRNA (230000 daltons) and the beta-chain mRNA and a dense and compact structure in the electron microscope (average length of the molecules 0.14 micron), which can be transformed to a linear structure (average length of the molecules 0.44 micron corresponding to a molecular weight of about 420000 daltons). The poly(A)-tail of the mRNA estimated by polyacrylamide gel electrophoresis with poly(A)-markers as reference substances has a size between 12 and 52 nucleotides. The mRNA works as a good template in the cDNA-synthesis with reverse transcriptase and full length copies of the mRNA were obtained by this reaction. The cDNA hybridizes to an amount of 70% with the globin mRNA at a 1:4 cDNA/mRNA ratio.