What does MSI mean in NASA?
This page is about the meanings of the acronym/abbreviation/shorthand MSI in the Governmental field in general and in the NASA terminology in particular.
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What does MSI mean?
- 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.