Definitions for MicroSatellite Instability
mi·crosatel·lite in·sta·bil·i·ty

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1. Microsatellite instability

   Microsatellite instability (MSI) is the condition of genetic hypermutability (predisposition to mutation) that results from impaired DNA mismatch repair (MMR). The presence of MSI represents phenotypic evidence that MMR is not functioning normally. MMR corrects errors that spontaneously occur during DNA replication, such as single base mismatches or short insertions and deletions. The proteins involved in MMR correct polymerase errors by forming a complex that binds to the mismatched section of DNA, excises the error, and inserts the correct sequence in its place. Cells with abnormally functioning MMR are unable to correct errors that occur during DNA replication and consequently accumulate errors. This causes the creation of novel microsatellite fragments. Polymerase chain reaction-based assays can reveal these novel microsatellites and provide evidence for the presence of MSI. Microsatellites are repeated sequences of DNA. These sequences can be made of units of 1 to 6 base pairs in length that are repeated and reside adjacent to each other in the genome. Although the length of microsatellites can vary from person to person and contributes to the individual DNA "fingerprint", each individual has microsatellites of a set length. The most common microsatellite in humans is a dinucleotide repeat of the nucleotides C and A, which occurs tens of thousands of times across the genome. Microsatellites are also known as simple sequence repeats (SSRs).

WikidataRate this definition:5.0 / 1 vote

1. Microsatellite instability

   Microsatellite instability is the condition of genetic hypermutability that results from impaired DNA Mismatch Repair. In other words, MSI is the phenotypic evidence that MMR isn't functioning normally. DNA MMR corrects errors that spontaneously occur during DNA replication like single base mismatches or short insertions and deletions. The proteins involved in MMR form a complex that binds to the mismatch, identifies the correct strand of DNA, then subsequently excises the error and repairs the mismatch. Cells with abnormally functioning MMR tend to accumulate errors rather than correcting those errors. As a result gene sequences are not preserved faithfully through DNA replication, and novel Microsatellites fragments are created. Microsatellite instability is detected by PCR based assays that reveal these novel microsatellites. There are two mechanisms that cause impaired MMR: 1. MMR gene mutation that results in a malfunctioning gene product 2. MMR gene product underproduction Microsatellite instability detects that MMR is functionally impaired, but does not imply the mechanism by which it is impaired. MSI-PCR can be used as a less expensive screening tool for MMR gene mutations that are confirmed by gene sequencing.

U.S. National Library of MedicineRate this definition:2.5 / 2 votes

1. Microsatellite Instability

   The occurrence of highly polymorphic mono- and dinucleotide MICROSATELLITE REPEATS in somatic cells. It is a form of genome instability associated with defects in DNA MISMATCH REPAIR.

How to pronounce MicroSatellite Instability?

1. Alex

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How to say MicroSatellite Instability in sign language?

Numerology

1. Chaldean Numerology

   The numerical value of MicroSatellite Instability in Chaldean Numerology is: 9

2. Pythagorean Numerology

   The numerical value of MicroSatellite Instability in Pythagorean Numerology is: 4

References

1. ^ Wikipedia
   https://en.wikipedia.org/wiki/Microsatellite_Instability
2. ^ Wikidata
   https://www.wikidata.org/w/index.php?search=MicroSatellite Instability