MRNA Stability

The stability of mRNA can also be regulated within the cytoplasm. Some mRNA have very short halflife (seconds to minutes), whereas others have longer half-lives (hours). This is important because some gene products (i.e., hormones and cell signals) must be short-lived and the body needs to control/ counterbalance their synthesis and action. A nutritionally important example of regulation of mRNA stability involves iron and the transferrin receptor. The transferrin receptor is the protein responsible for the uptake of iron into cells. The expression of the transferrin receptor is downregulated by iron in order to limit uptake and potential toxicity of the mineral at times of high availability. This regulation is achieved through an iron regulatory protein. When iron is limited, this protein is bound to the 3' untranslated region of the transferrin receptor mRNA. This serves to protect the mRNA from degradative attack and permits its continued translation into active protein. As iron concentrations rise, the binding protein becomes occupied with iron, which results in its dissociation from the transferrin receptor mRNA. The mRNA is then degraded more quickly, concentrations fall, and protein production is limited.

Breaking Bulimia

Breaking Bulimia

We have all been there: turning to the refrigerator if feeling lonely or bored or indulging in seconds or thirds if strained. But if you suffer from bulimia, the from time to time urge to overeat is more like an obsession.

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