- This explains why some people, although cured, are tested positive again for SARS-CoV-2 months later.
- The first pre-publication, last December and deleted, was severely criticized for lack of adequate evidence.
- This time, the researchers put forward more evidence, but their results were found in the laboratory and deserved confirmation.
Can we believe it? American researchers from the prestigious Massachusetts Institute of Technology (MIT) have provided new evidence suggesting that SARS-CoV-2 genes may be incorporated into our DNA. In a study published PNAS, They show, thanks to the culture of cells in the laboratory, how genetic fragments of the coronavirus fuse into our chromosomes. They also claimed to have “There is undoubted evidence that the coronavirus sequences are genetically matched”. This may explain why SARS-CoV-2 will be tested positive again after 2 months, even if there is no cure, despite evidence of viral replication.
The first previous publication was deleted
To reach these conclusions, researchers rely on the ability of an enzyme in human cells to convert viral sequences into DNA for insertion into our chromosomes. This enzyme, reverse transcriptase, is encoded by the elements LINE-1 (L1), which make up about 17% of the human genome and represent artifacts of past infections with retroviruses. These elements are very inactive, but some, called retrotranspositions, have the ability to move spontaneously in the gene.
Researchers have used this premise to study during laboratory experiments whether a similar approach occurs with coronavirus artefacts. In a publication published last December, they argued that when human cells rich in LINE-1 elements become infected with the coronavirus, DNA versions of the SARS-CoV-2 sequences nest in the cell chromosomes. These results have garnered numerous reviews for their authors and are a pre-publication that should be removed. Among critics, British researchers point to a study previously published in the March 5 issue of the journal bioRxiv, Because the chimeras of the viral-human DNA were systematically created, the technology used made it possible to identify them on chromosomes. The study, conducted by Chinese researchers, was published in the February 25 issue of the journal Boundaries in Cellular and Infectious Microbiology, Stated that the coronavirus interacts with endogenous retrotransposition in human cells.
In this new research, scientists at MIT have provided new evidence that artifacts alone cannot explain the discovered levels of viral-human chimeric DNA. Furthermore, they showed that components of LINE-1 elements frame the viral gene sequence, suggesting that SARS-CoV-2 RNA sequences can be reverse transcripted and integrated with the gene of the infected cell. Virus with human cell ranges.
Results that confuse other professionals
For Cedric Feschot, who studies endogenous retrovirus fragments in the human genome at Cornell University, a hypothesis proposed by MIT researchers “Acceptable“But more evidence is needed before scientists can say that the virus can enter a gene. “Consolidation data in cell culture is much more reliable than those presented in the preprint, but this is still not entirely clear.He said in an article published in the magazine Science. In addition, the submitted data is only the result of laboratory manipulation. “The clinical or biological significance of these observations, if any, is a matter of pure ulation at this point.”, He believes.
Journal article Science Harmeet Malik, an expert on the ancient viruses of the human genome, was also quoted at Fred Hutchinson Cancer Research Center In Seattle, Is related to the question of why people who need to remove the virus permanently get positive results in PCR tests. However, the explanation provided by the MIT researchers disturbed him.Reverse transcription mechanisms are available under normal circumstances”In human cells.