Under Iron-Starvation Conditions in the Cell

Question

Under iron-starvation conditions in the cell,
A) cytosolic aconitase binds to the 3′ UTR of the mRNA encoding the transferrin receptor.
B) cytosolic aconitase binds to the 3′ UTR of the mRNA encoding ferritin.
C) cytosolic aconitase blocks translation of the mRNA encoding the transferrin receptor.
D) the mRNA encoding the transferrin receptor is cleaved by an endonuclease.
E) All of the above.

Accepted Answer

The iron-sensitive RNA-binding protein aconitase can bind to the 3′ untranslated region (UTR) of the transferrin receptor mRNA and increase production of the receptor by blocking endonucleolytic cleavage of the mRNA. The addition of iron to cells results in the release of aconitase from the mRNA and thus decreases the stability of the mRNA.