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Samantha-Craven

Page history last edited by Samantha Craven 14 years, 11 months ago

Welcome to your Wiki Page

 

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mRNA: Iron Response Element

 

Protein: Iron Response Proteins

 

 

 

Structure

 

Iron Response Element

 

                          

Image 1.                                                                         Image 2.

3-D Structure of Iron Response Element made of mRNA     The Base Structures of mRNA Iron Response Elements

 

  • The nucleotide sequence of the Iron Response Element differs among organisms and what gene it is associated with (Piccinelli.)

 

Mechanism Overview

 

 

Translation

 

  •  The Iron Response Element and Iron Response Protien are involved in Translation. Translation is the process in which the mRNA code is translated into protien (http://nobelprize.org/). The Iron Response Element is a hairpin loop on mRNA upstream or downstream from a gene in which code for a protein whose function is involved in iron metabolism (http://nobelprize.org/). The Iron Resposne Element interactions with the Iron Response Protien can positively or negatively regulate translation of that gene on the mRNA (http://nobelprize.org/).                      

 

   

 

 

Function

  • The Iron Response Element (IRE) is a section of mRNA that folds on itself to form a hair-pin structure, which is bound by an Iron Response Protein (IRP) (Meyron-Holtz et. al.) The binding of the Iron Response Protein causes the positive or negative control of a gene, according to the relative concentration of iron in it's surrondings (Hentze et. al.) 
  • Their are two major protiens associated with the control of the bodies intake of Iron; Transferrin and Ferritin (Wallander et. al). Both proteins are controled by the binding of the Iron Response Proteins to the Iron Response Elements (Hentze et. al.)
  • Transferrin - When iron concentration is low (sickle.bwh.havard.edu.)Transferrin acts as a transport protein of iron (sickle.bwh.havard.edu.) It can bind two iron atoms in the Fe(III) state and bring them into the cell by vessicles (sickle.bwh.havard.edu.)
  • Ferritin - When iron concentration is high ( Tsuji.) Ferrintin acts as a storage protein of iron and can store up to 4500 atoms of iron (Tsuji.) It will bind the excess iron and will release iron in a constant controlled fashion that is not toxic to the body.

Iron, brain ageing and neurodegenerative disorders

 

Image 7.

The simplistic control of Transferrin and Ferritin by the Iron Response Element and Iron Response Protien.

 

  • As Iron concentration in the body increases the Iron Response Protein will be bound by iron disabling, so that it cannot bind to the Iron Response Element (www.nature.com.). This event causes the gene to "turn on" in the Ferritin sequence and is translated into protein (www.nature.com.).   When the Iron Response Protein bound to the mRNA of the Tranferrin the mRNA is destroyed (hence the trash can) (www.nature.com.).  
  • As iron concentration in the body decreases the Iron Response Protein will bind to the Iron Response Element(www.nature.com.).  The binding event stables the Transferrin mRNA and enables translation (www.nature.com.). The binding event in the Ferritin "turns off" the gene, disabling translation (www.nature.com.). 

 

  

Image 8.

The known systems in the body that involve Iron Response Elements and Iron Response Proteins.

 

Diseases

 

Haemochromatosis Type 4 

This disease is caused by Iron-overload (www.ncbi.nlm.nih.gov.). The organs effected are the heart, skin ,pancreas, joints, and liver (www.ncbi.nlm.nih.gov.). Haemochromatosis can be caused by a point-mutation in L Ferritin (www.ncbi.nlm.nih.gov.). It has been suggested that the mutation may be in the Iron Response Element (www.ncbi.nlm.nih.gov.). The Gene Locus is 19q13.3-q13.4.The treatment for this disease is to watch iron intake and give blood (http://www.cdc.gov/.

 

 

Hyperferritinemia-cataract syndrome

Hyperferritinemia-cataract syndrome is an onset of cataracts in both eyes early in life (www.ncbi.nlm.nih.gov. ) It is an autosomal dominant disease in which ferritin gene expression is no longer controled by the Iron Binding Protein (www.iovs.org.).  With this mutation, ferritin can be transcribed without the influence of iron (www.iovs.org.) 

 

 

 

 

 

 

 

Comments (1)

Christopher Korey said

at 4:18 pm on Apr 6, 2009

Really nice job. I like the first two images of the sequence hair-pin loop. I would get rid of figures 3-6. You don't need to go into much detail about translation except where it is impacted by the IRE. This information will be elsewhere. Focus just on your process. The sections on Iron regulation are great. For the disease section just short paragraphs for each disease and then link out to more detailed discussions on OMIM or other sites. You want the reader to have more information if they would like it, but not necessarily on the page. Remember to reference in the text with footnotes and put a standard reference in and then use your URLs that you have listed under sources to make the link active.

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