title: Demonstration of globin messenger sequences in giant nuclear precursors of messenger RNA of avian erythroblasts.
abstract: Highly purified globin mRNA from ducks was copied with RNA-directed DNA polymerase from avian myeloblastosis virus into anti-messenger DNA. With excess RNA, more than 90% of this DNA annealed back to its template with a C(o)t/2 value of 7.5 x 10(-4) mol.sec. liter(-1); the melting temperature of the hybrid was 86 degrees . Giant nuclear RNA fractions with sedimentation coefficients of more than 50 S formed hybrids of almost equal stability at C(o)t/2 values of 0.05-0.42 mol.sec. liter(-1), indicating amRNA content of 0.3-1.5%. 12S RNA from the same polyribosomes and nuclear giant RNA from HeLa cells did not cross-hybridize. Although a large part of the giant RNA broke down in 99% dimethylsulfoxide gradients, RNA fractions sedimenting faster than 28S rRNA still were found to consist of up to 0.03% globin mRNA sequences. Thus, the mRNA sequences are contained in the covalent structure of giant nuclear precursors, which are termed precursor-mRNA.
mesh_terms: D000818:Animals; D001354:Avian Leukosis Virus / Q000201:enzymology / Q000378:metabolism; D001483:Base Sequence; D002499:Centrifugation, Density Gradient; D004279:DNA, Viral / Q000096:biosynthesis / Q000378:metabolism; D004372:Ducks; D004912:Erythrocytes / Q000378:metabolism*; D005914:Globins / Q000096:biosynthesis*; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization; D009711:Nucleotides / Q000032:analysis*; D012333:RNA, Messenger / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D013698:Templates, Genetic
chemical_list: D004279:DNA, Viral; D009711:Nucleotides; D012333:RNA, Messenger; D005914:Globins; D012194:RNA-Directed DNA Polymerase