Expression of the genes for the ferritin H and L subunits in rat liver and heart. Evidence for tissue-specific regulations at pre- and post-translational levels.
The proportion of ferritin light-chain and heavy-chain subunits (L and H) present in the ferritin multimeric shell varies between different tissues. To identify the regulatory mechanisms responsible for the greater amount of L in liver than in heart isoferritins, we analysed ferritin-gene expression at the RNA and protein levels in these two tissues of the rat. In the heart the ratio between the amount of L and H, at the level both of synthesis and accumulation, is about 1 and is the same as the ratio between their respective mRNAs. In contrast, in the liver, the ratio between the L- and H-mRNAs is approx. 2 and cannot entirely explain the large predominance of L in isoferritins in this tissue. Since in the liver the L-mRNA is neither preferentially associated with polyribosomes nor translated more efficiently than its H- counterpart, it seems that the liver-specific isoferritin profile is determined by a combination of pre- and post-translational mechanisms, whereas in heart the post-translational regulation does not seem to be relevant and the tissue-specific pattern is determined at the level of mRNA accumulation.
Cairo
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Istituto di Patologia Generale dell'Università degli Studi Centro di Studio sulla Patologia Cellulare del CNR, Milano, Italy.
Rappocciolo
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Tacchini
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L
Schiaffonati
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L
D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D005293:Ferritins / Q000235:genetics*; D005786:Gene Expression Regulation; D007163:Immunosorbent Techniques; D008099:Liver / Q000378:metabolism*; D046911:Macromolecular Substances; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D046911:Macromolecular Substances; D012333:RNA, Messenger; D005293:Ferritins