title: The nature of the 5'-linked 5' nucleotide sequence at the 5' end of rabbit globin messenger ribonucleic acid.
abstract: Poly(A)-containing messenger RNA isolated from rabbit reticulocytes as estimated by periodate oxidation and condensation with [3H]isoniazid has two oxidizable end groups per molecule of mol. wt. 220000. When the mRNA is subjected to stepwise degradation by beta-elimination, only one oxidizable end-group is found. This indicates that one of the 2',3' hydroxyl end-groups is linked through the normal 3'--5' phosphodiester bond, but that the other is linked in such a way that after stepwise degradation no new 2',3 hydroxyl group is revealed. This structure could be a 5'-linked 5'-phospho di- or tri-ester. On digestion with ribonuclease the isoniazid-labelled RNA produced oligonucleotide hydrazones consistent with a poly(A) sequence at the 3' end plus fragments that are not found after stepwise degradation. These fragments have a charge of --6 and --8 from pancreatic ribonuclease or --7 from ribonuclease T1 digestion. These charges are changed to --3.4 and --4.1 after pancreatic ribonuclease, ribonuclease T2 and alkaline phosphatase digestion. methyl-3H-labelled-poly(A)-containing RNA isolated from late erythroid cells contain a methyl-labelled fragment resistant to endonuclease and phosphodiesterase II digestion. After digestion with phosphodiesterase I this fragment produces methyl-3 H-labelled nucleotides with the electrophoretic mobility of pm7G and pAm. It is concluded that globin mRNA has the 5' sequences m7G(5')ppp'AmpYpGp ... and m7G(5')pppAmpApGpYp.
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002845:Chromatography; D004586:Electrophoresis; D005914:Globins; D007538:Isoniazid; D008970:Molecular Weight; D009691:Nucleic Acid Denaturation; D011061:Poly A; D012333:RNA, Messenger / Q000032:analysis*; D011817:Rabbits; D012260:Ribonucleases
chemical_list: D012333:RNA, Messenger; D011061:Poly A; D005914:Globins; D012260:Ribonucleases; D007538:Isoniazid