Scientists have discovered that in laboratory-grown cells containing RNA repeats and proteins derived from them,
Clusters can press and deform the core,influence how molecules enter and leave it. They also trap other molecules so they can't do their job and eventually kill the cell.
One of the types of molecules that capturecytoplasmic accumulations, - RNA-binding proteins. They are involved in gene expression. These proteins are known to mislocalize in re-expansion disorders. But the mechanism of how this happens is not entirely clear. The authors of the new study believe that the answer is in cytoplasmic RNA clusters - RNA-binding proteins get stuck inside them.
There are four types of molecules in human DNA:adenine, cytosine, thymine and guanine. These are known as nucleotides, which run along the strands that make up chromosomes. Since there are only four of them, it is not surprising that a short DNA sequence is repeated somewhere in the genome. However, when this happens too many times in a row (tens or hundreds), it becomes a problem for the cells. Re-expansion disorders are a category of neurological disorders caused by excessive repetition. They cause neurodegeneration, muscular dystrophy and various disorders in the brain.
As a result, some bases in RNA canstick to each other, and long strands of RNA with "repeats" are very prone to tangling. For example: in the same way, a long piece of tape is more likely to curl up and stick to itself than a short one.
The results of the study are published in the journal Proceedings of the National Academy of Sciences (PNAS).
</ p>Cover: Solid clumps of repeat-containing RNA (bright green) and protein deform the cell nucleus (blue). Credit: Michael Das/Whitehead Institute