Translational regulation of ferritin synthesis in rat liver. Effects of chronic dietary iron overload.
In rats with chronic dietary iron overload, a higher amount of liver ferritin L-subunit mRNA was found mainly engaged on polysomes, whereas in control rats ferritin L-subunit mRNA molecules were largely stored in ribonucleoprotein particles. On the other hand, ferritin H-subunit mRNA was unchanged by chronic iron load and remained in the inactive cytoplasmic pool. In agreement with previous reports, in rats acutely treated with parenteral iron, only the ferritin L-subunit mRNA increased in amount, whereas both ferritin subunit mRNAs shifted to polysomes. This may indicate that, whereas in acute iron overload the hepatocyte operates a translation shift of both ferritin mRNAs to confront rapidly the abrupt entry of iron into the cell, during chronic iron overload it responds to the slow iron influx by translating a greater amount of L-subunit mRNA to synthesize isoferritins more suitable for long-term iron storage.
Cairo
G
G
Istituto di Patologia Generale, Centro di Studio sulla Patologia Cellulare CNR, Milano, Italy.
Tacchini
L
L
Schiaffonati
L
L
Rappocciolo
E
E
Ventura
E
E
Pietrangelo
A
A
D000818:Animals; D015342:DNA Probes; D004032:Diet; D005260:Female; D005293:Ferritins / Q000096:biosynthesis / Q000235:genetics*; D005786:Gene Expression Regulation / Q000187:drug effects*; D007501:Iron / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D046911:Macromolecular Substances; D011132:Polyribosomes / Q000187:drug effects / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
D015342:DNA Probes; D046911:Macromolecular Substances; D012333:RNA, Messenger; D005293:Ferritins; D007501:Iron