MSH3: Difference between revisions

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Magnetic Resonance Imaging (MRI)
{{DISPLAYTITLE:MSH3}}


Magnetic Resonance Imaging (MRI) is a non-invasive imaging technology that produces three-dimensional detailed anatomical images. It is often used for disease detection, diagnosis, and treatment monitoring. MRI is based on sophisticated technology that excites and detects the change in the direction of the rotational axis of protons found in the water that makes up living tissues.
== Overview ==
[[File:3THX-MutSb-complex-of-MSH2-MSH3.png|thumb|right|300px|Crystal structure of the MutSb complex of MSH2-MSH3.]]
'''MSH3''' is a gene that encodes a protein involved in the [[DNA mismatch repair]] (MMR) system. This system is crucial for maintaining genomic stability by correcting errors that occur during [[DNA replication]]. MSH3 forms a heterodimer with [[MSH2]], another protein in the MMR pathway, to recognize and initiate repair of insertion-deletion loops and other mismatches in the DNA.


== History ==
== Function ==
The development of MRI is a story of scientific innovation and collaboration. The principles of MRI were first discovered in the early 20th century, but it wasn't until the 1970s that the first MRI machines were developed. [[Paul Lauterbur]] and [[Peter Mansfield]] were awarded the Nobel Prize in Physiology or Medicine in 2003 for their discoveries concerning magnetic resonance imaging.
The MSH3 protein, in conjunction with MSH2, forms the MutSb complex. This complex is specifically involved in the repair of insertion-deletion loops, which are common errors that occur during [[DNA replication]] and [[recombination]]. The MutSb complex recognizes these errors and recruits other proteins to excise the incorrect DNA segment and resynthesize the correct sequence.


== Principles of MRI ==
== Structure ==
MRI is based on the principles of nuclear magnetic resonance (NMR), a spectroscopic technique used to obtain microscopic chemical and physical information about molecules. When placed in a magnetic field, certain nuclei resonate at a characteristic frequency. MRI uses this principle to image the body.
[[File:3THX-MutSb-complex-of-MSH2-MSH3.png|thumb|left|300px|Detailed view of the MSH2-MSH3 interaction.]]
The structure of the MSH3 protein, as part of the MutSb complex, has been elucidated through [[X-ray crystallography]]. The complex is composed of two main domains: the mismatch recognition domain and the ATPase domain. The mismatch recognition domain is responsible for binding to the DNA and identifying errors, while the ATPase domain provides the energy required for the repair process.


=== Magnetic Field ===
== Clinical Significance ==
The MRI machine generates a powerful magnetic field that aligns the magnetization of hydrogen atoms in the body. Radiofrequency currents are then used to systematically alter the alignment of this magnetization. When the radiofrequency field is turned off, the MRI sensors are able to detect the energy released as the hydrogen atoms return to their baseline states.
Mutations in the MSH3 gene can lead to defects in the DNA mismatch repair system, resulting in increased susceptibility to certain types of [[cancer]], particularly [[colorectal cancer]]. MSH3 mutations are also associated with [[hereditary nonpolyposis colorectal cancer]] (HNPCC), also known as [[Lynch syndrome]].


=== Radiofrequency Pulses ===
== Related Proteins ==
The radiofrequency pulses are used to disturb the alignment of the hydrogen atoms. The frequency of these pulses is specific to the type of tissue being imaged, allowing for detailed images of different types of tissues.
MSH3 is part of a family of proteins that includes [[MSH2]], [[MSH6]], and [[MSH1]]. These proteins work together in various combinations to recognize and repair different types of DNA mismatches. The MSH2-MSH6 complex, known as MutS_, primarily repairs base-base mismatches and small insertion-deletion loops, while the MSH2-MSH3 complex, MutSb, is more specialized for larger insertion-deletion loops.


=== Image Formation ===
== Related Pages ==
The signals emitted by the hydrogen atoms are detected by the MRI machine and are used to construct an image. The data is processed using Fourier transformation to produce a detailed image of the inside of the body.
* [[DNA mismatch repair]]
* [[MSH2]]
* [[MSH6]]
* [[Lynch syndrome]]
* [[Colorectal cancer]]


== Applications ==
[[Category:DNA repair]]
MRI is used in radiology to investigate the anatomy and physiology of the body in both health and disease. It is particularly useful for imaging the brain, muscles, heart, and cancers compared to other medical imaging techniques such as [[computed tomography]] (CT) or [[X-ray]]s.
[[Category:Genes on human chromosome 5]]
 
[[Category:Proteins]]
=== Neurology ===
MRI is the imaging modality of choice for neurological cancers, as it provides better contrast in soft tissues than CT. It is also used to diagnose and monitor diseases such as multiple sclerosis, stroke, and brain tumors.
 
=== Cardiology ===
In cardiology, MRI is used to assess the structure and function of the heart. It can provide information on myocardial infarction, cardiomyopathies, and congenital heart disease.
 
=== Oncology ===
MRI is used to detect and monitor tumors in various parts of the body. It is particularly useful for imaging soft tissue tumors and cancers of the brain, spine, and musculoskeletal system.
 
== Safety ==
MRI is generally considered safe, as it does not use ionizing radiation. However, the strong magnetic fields can pose risks to patients with certain implants, such as pacemakers. It is important to screen patients for contraindications before undergoing an MRI scan.
 
== Limitations ==
While MRI is a powerful diagnostic tool, it has limitations. It is expensive and not as widely available as other imaging modalities. Additionally, it is not suitable for patients with certain types of metal implants.
 
== Also see ==
* [[Computed Tomography]]
* [[X-ray]]
* [[Ultrasound]]
* [[Nuclear Medicine]]
 
{{Medical Imaging}}
 
[[Category:Medical Imaging]]
[[Category:Radiology]]
[[Category:Magnetic Resonance Imaging]]

Latest revision as of 11:41, 15 February 2025


Overview[edit]

Crystal structure of the MutSb complex of MSH2-MSH3.

MSH3 is a gene that encodes a protein involved in the DNA mismatch repair (MMR) system. This system is crucial for maintaining genomic stability by correcting errors that occur during DNA replication. MSH3 forms a heterodimer with MSH2, another protein in the MMR pathway, to recognize and initiate repair of insertion-deletion loops and other mismatches in the DNA.

Function[edit]

The MSH3 protein, in conjunction with MSH2, forms the MutSb complex. This complex is specifically involved in the repair of insertion-deletion loops, which are common errors that occur during DNA replication and recombination. The MutSb complex recognizes these errors and recruits other proteins to excise the incorrect DNA segment and resynthesize the correct sequence.

Structure[edit]

Detailed view of the MSH2-MSH3 interaction.

The structure of the MSH3 protein, as part of the MutSb complex, has been elucidated through X-ray crystallography. The complex is composed of two main domains: the mismatch recognition domain and the ATPase domain. The mismatch recognition domain is responsible for binding to the DNA and identifying errors, while the ATPase domain provides the energy required for the repair process.

Clinical Significance[edit]

Mutations in the MSH3 gene can lead to defects in the DNA mismatch repair system, resulting in increased susceptibility to certain types of cancer, particularly colorectal cancer. MSH3 mutations are also associated with hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome.

Related Proteins[edit]

MSH3 is part of a family of proteins that includes MSH2, MSH6, and MSH1. These proteins work together in various combinations to recognize and repair different types of DNA mismatches. The MSH2-MSH6 complex, known as MutS_, primarily repairs base-base mismatches and small insertion-deletion loops, while the MSH2-MSH3 complex, MutSb, is more specialized for larger insertion-deletion loops.

Related Pages[edit]

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