Table of Contents
- 1 How is ferritin translation regulated?
- 2 How is the process of transcription regulated?
- 3 How does iron regulate transferrin receptor gene expression?
- 4 What is the role of ferritin?
- 5 Why would transcription have to be regulated?
- 6 Where does transcription occur in eukaryotes?
- 7 How is iron released from ferritin?
- 8 How does the body regulate iron?
- 9 What is Frank Torti’s theory of ferritin regulation?
- 10 What are the subunits of ferritin?
How is ferritin translation regulated?
Translational regulation of ferritin by oxidative stress. Ferritin is subject to translational control by the IRE binding proteins IRP-1 and IRP-2. When activated, these proteins can bind to the IRE in the 5′ UTR of ferritin H or L mRNA and inhibit translation of the mRNA.
How is the process of transcription regulated?
First, transcription is controlled by limiting the amount of mRNA that is produced from a particular gene. The second level of control is through post-transcriptional events that regulate the translation of mRNA into proteins. Even after a protein is made, post-translational modifications can affect its activity.
Where does transcriptional regulation occur?
Prokaryotic transcription and translation occur simultaneously in the cytoplasm, and regulation occurs at the transcriptional level. Eukaryotic gene expression is regulated during transcription and RNA processing, which take place in the nucleus, and during protein translation, which takes place in the cytoplasm.
How does iron regulate transferrin receptor gene expression?
For most non-erythroid cells, iron can regulate the TfR expression in a reciprocal manner through modulating the stability of the receptor mRNA whereas in hemoglobin-synthesizing cells, the TfR expression is independent of the cellular iron loading.
What is the role of ferritin?
Ferritin is a protein that stores iron inside your cells. You need iron to make healthy red blood cells. Red blood cells carry oxygen from your lungs to the rest of your body. Iron is also important for healthy muscles, bone marrow, and organ function.
How is transcription controlled regulated in prokaryotes and eukaryotes?
As already discussed, transcription in bacteria is regulated by the binding of proteins to cis-acting sequences (e.g., the lac operator) that control the transcription of adjacent genes. The eukaryotic regulatory sequences are usually ligated to a reporter gene that encodes an easily detectable enzyme.
Why would transcription have to be regulated?
A single gene can be regulated in a range of ways, from altering the number of copies of RNA that are transcribed, to the temporal control of when the gene is transcribed. This control allows the cell or organism to respond to a variety of intra- and extracellular signals and thus mount a response.
Where does transcription occur in eukaryotes?
The eukaryotic nucleus therefore provides a distinct compartment within the cell, allowing transcription and splicing to proceed prior to the beginning of translation. Thus, in eukaryotes, while transcription occurs in the nucleus, translation occurs in the cytoplasm.
How do transcription factors regulate gene expression in eukaryotes?
Transcription factors are proteins that regulate the transcription of genes—that is, their copying into RNA, on the way to making a protein. Transcription factors help ensure that the right genes are expressed in the right cells of the body, at the right time.
How is iron released from ferritin?
Thus, in order for iron to be released from ferritin, the mineral lattice must be dissolved (i.e., to allow the iron atoms to break away from the lattice structure). This removal is accomplished by reducing iron from the Fe(III) (ferric) oxidation state to the Fe(II) (ferrous) oxidation state.
How does the body regulate iron?
At the whole-body level, dietary iron absorption and iron export from the tissues into the plasma are regulated by the liver-derived peptide hepcidin. When tissue iron demands are high, hepcidin concentrations are low and vice versa. Too little or too much iron can have important clinical consequences.
How is cytoplasmic ferritin regulated?
The content of cytoplasmic ferritin is regulated by the translation of ferritin H and L mRNAs in response to an intracellular pool of “chelatable” or “labile” iron. 45, 46 Thus, when iron levels are low, ferritin synthesis is decreased; conversely, when iron levels are high, ferritin synthesis increases.
What is Frank Torti’s theory of ferritin regulation?
Frank M. Torti, Suzy V. Torti; Regulation of ferritin genes and protein. Blood 2002; 99 (10): 3505–3516. doi: https://doi.org/10.1182/blood.V99.10.3505 Increasingly, perturbations in cellular iron and ferritin are emerging as an important element in the pathogenesis of disease.
What are the subunits of ferritin?
Ferritin is a ubiquitous and highly conserved iron-binding protein. In vertebrates, the cytosolic form consists of 2 subunits, termed H and L. Twenty-four ferritin subunits assemble to form the apoferritin shell.
Why is ferritin important in the pathophysiology of hemochromatosis?
These changes in ferritin are important not only in the classic diseases of iron acquisition, transport, and storage, such as primary hemochromatosis, but also in diseases characterized by inflammation, infection, injury, and repair.