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THE PATTERN OF METHYLATION OF RNA IN PERIPHERAL NERVE OF THE CHICK DURING DEVELOPMENT 1
Author(s) -
Mezei Catherine,
Hu Y.W.
Publication year - 1972
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1972.tb05117.x
Subject(s) - rna , uridine , methionine , methylation , biology , ribosomal rna , embryogenesis , population , biochemistry , microbiology and biotechnology , embryo , myelin , endocrinology , amino acid , central nervous system , dna , demography , sociology , gene
The pattern of the methylation of RNA was investigated in organ cultures of the sciatic nerve of the chicken. Nerve tissue from 14‐day embryos, 17‐day embryos and 3‐day‐ old chicks was incubated with [methyl‐ 3 H]methionine or with [2‐ 14 C]uridine and [methyl‐ 3 H]methionine simultaneously for various periods of time. Subsequently, RNA was extracted from the tissues and the purified preparations were fractionated by polyacrylamide gel electrophoresis. The electrophoretic patterns of the rapidly labelled RNA changed during the three developmental stages. The incorporation of both uridine and the methyl groups from methionine was highest in the‘heavy’RNA species of the 14‐day embryonic nerve during the 0.5 and 1.0 h incubation periods. In contrast, in the nerves of 3‐day‐old chicks during a 0.5 h pulse with both precursors, methylation was almost entirely limited to the transfer RNA species. Furthermore, the incorporation of uridine in the nerves from 3‐day‐old animals revealed the presence of a heterogeneous population of rapidlylabelled, unmethylated species of RNA, most of which migrated between the smaller ribosomal RNA and transfer RNA components of the bulk RNA. The pattern of uridine incorporation and the methylation of the rapidly‐labelled RNA of the 17‐day embryonic nerve represented a transitional state between that of the 14‐day embryos and that of the 3‐day‐old chicks. The 17‐day embryonic stage of development corresponded to the phase of the onset of rapid deposition of myelin lipids in the sciatic nerve. Pulse‐chase experiments on the embryonic nerves indicated that a number of methylated precursors of ribosomal RNA and labile, heterogeneous, probably DNA‐like RNA were synthesized.