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Hypoxia Specifically and Reversibly Induces the Synthesis of Ferritin in Oligodendrocytes and Human Oligodendrogliomas
Author(s) -
Qi Yan,
Dawson Glyn
Publication year - 1994
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 - 10.1046/j.1471-4159.1994.63041485.x
Subject(s) - ferritin , western blot , microbiology and biotechnology , oligodendrocyte , cycloheximide , immunoprecipitation , immunocytochemistry , biology , hypoxia (environmental) , biochemistry , neuroglia , amino acid , protein biosynthesis , chemistry , endocrinology , central nervous system , myelin , gene , organic chemistry , oxygen
Neonatal (3 day old) rat oligodendrocytes grown in monolayer culture and exposed to increasingly hypoxic culture conditions showed increased Tran 35 S‐label incorporation into a 22‐kDa protein. Reoxygenation of cultures reversed the synthesis of the protein. Amino acid sequencing of a peptide derived from the purified protein revealed a 13 amino acid sequence with complete identity to a human heavy chain subunit of ferritin. This was confirmed by two‐dimensional gel electrophoresis, immunoprecipitation, and western blot analysis with anti‐ferritin antibody. In addition, hypoxia was able to induce the synthesis of ferritin in a cell line derived from human oligodendroglioma cells but not in astrocytes or neurons. Actinomycin D (1–15 µg/ml) treatment did not block the hypoxic induction of ferritin synthesis, whereas cycloheximide (1 µ M ) gave complete inhibition. Northern blot analysis showed that ferritin mRNA levels remained unchanged in both control and hypoxic oligodendrocytes and human oligodendroglioma cells, suggesting that the synthesis of ferritin was translationally rather than transcriptionally regulated by hypoxia. In neither oligodendrocytes nor the oligodendroglioma was there any cross‐reaction with an antibody to αB‐crystallin, the 22‐kDa protein induced in astrocytes by various types of stress, further suggesting the specificity of hypoxic induction of ferritin in oligodendrocytes.