Poles show how the cell fights parasites "jumping genes"
Some of the smallest parasites we carry inside us are. jumping genes. Fortunately, our cells have ways to keep these genetic parasites from multiplying. Polish team in the prestigious "Cell" explained a new defense mechanism against the so-called. retrotransposons.
Some of the smallest parasitesóin, which inhabit the human body, are the so-called “winds”. retrotransposons. These are simply DNA fragments woven into our genome. They do nothing for "good wspólnego" of the entire organism, but only produce machinery to copy themselves. So their goal is to paste their own copies into DNA. In this wayób their genes can "jump" after our DNA.
Retrotransposons are not the same thing as viruses, explains Prof. J. K. K., in an interview with PAP. Andrzej Dziembowski of the Institute of Biochemistry and Biophysics of the Polish Academy of Sciences in Warsaw. The viruses have a casing, która allows them to come out of the comórk and attack subsequent comórki. Retrotrasposons are unable to leave the comórki: multiply in the DNA of the same cellórki, from whichóderive. They are transferred from generation to generation m.in. because they are also present in the comóreproductive organs.
Either way, genetic parasites are making quite a mess in our genome. – As many as 17 percent. The DNA in the human genome is LINE-1 elements encoding the so-called “LINE-1”. retrotransposons – said. His teamóa group of young scientistsów, dr. Zbigniew Warkocki – the first author of the publication, Dr. Paweł Krawczyk and Dorota Adamska have just published in the prestigious journal "Cell" An article showing a hitherto unknown wayób, in which the comórka can block these little gene smarts from multiplying further.
As the scientist explained, each of us has in our comórkach between 80 and 100 active retrotransposonów. – We do not need them for anything, in fact they are harmful – mówi scientist. By inserting themselves into DNA, they lead to mutations and often accompany or even underlie tumorigenesis.
Prof. Dziembowski tells us that, for example. If in a human comóThe mechanism has already been described, e.g., the inability of the cells to properly fight retrotransposonów, this may be related to e.g. with complete infertility. And this is not the end of the problemów. Therefore, in comórks have developed defense mechanisms against the proliferation of these gene parasitesów.
A scientist explains how the copying of the geneów-parasiteów. LINE-1 elements are written in our DNA in the nucleus of comórkowe. There DNA is transcribed into RNA, które able to replicate DNA and paste it into the DNA of the same cellórki on the principle of the mechanism "copy-paste".
So far we have already described, for example. as cellsórka can – by means of methylation – block swój DNA fragment with the LINE-1 element so that it becomes inactive. Thus, in ogóle was not transcribed. Thus, the mechanisms were known, whichóre do not allow retrotransposon in ogóle began to copy. Now Polish scientists have explained how comórka can defend itself against genetic parasites at a later stage – when the retrotransposon has already become active.
Polish teamóHe discovered that in order to suppress "invasion" genetic parasite, in the comórce can take place in the so-called. RNA retrotransposon uridylation. It involves attaching additional nucleotides to the end of the RNAóin uridyls, whichóThey act as a crutch. – We have described for the first time how this mechanism works – mówi scientist from IBB PAN. Such blocked RNA is no longer dangerous. With its ball and chain, it can no longer jump around the genome and paste new fragments into itóin DNA. And over time it is removed by the comórka.