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Our cells may be USING supposed “parasite” DNA from viruses

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Here.

This story is part of a fundamental rethinking taking place in genomic science. In 2009, members of the FANTOM Consortium project reported that an important fraction of mammalian transcriptomes—meaning the RNA transcribed from the genome—consists of transcripts derived from retrotransposon elements, vestiges of ancient retroviruses from the same family as HIV that have in the past been considered to only parasite the genome. However, the biological function of these “jumping DNA”-associated RNA transcripts remained unknown.

In the current study on embryonic stem (ES) cells and induced pluripotent stem (iPS) cells using four high-throughput methods including cap analysis gene expression (CAGE), the researchers found that thousands of transcripts in stem cells that have not yet been annotated are transcribed from retrotransposons, presumably to elicit nuclear functions. These transcripts were found to be expressed in stem cells, but not differentiated cells. Importantly, the work showed that several of these transcripts are involved in the maintenance of pluripotency, since degrading several of them using RNA interference caused iPS cells to lose their pluripotency and differentiate.

These transcripts appear to have been recruited, surprisingly both in the human and mouse genome, where they are used to maintain the pluripotency of stem cells. Somehow, organisms including humans appear to have recruited viral elements into their genome in a way that helps to maintain the pluripotency of stem cells that allow them to regenerate. Why this is so remains a mystery for future investigation. More.

It’s not like recruitment strategies could be part of the kit or anything, right?

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8 Replies to “Our cells may be USING supposed “parasite” DNA from viruses

  1. 1
    gpuccio says:

    Long live transposons!

    They are the perfect algorithmic tool with basic random activity that a designer can use to intelligently remodel the genome.

  2. 2
    Querius says:

    So perhaps at least some viruses were originally beneficial, like the patches we install to upgrade some of our software.

    -Q

  3. 3
    snelldl says:

    If I remember correctly, one of the debates that gets referenced here every so often has Dr. Sternberg summarizing a paper from 2004 (I think) that did knock out experiments on retrotransposons. What they found was that taking the sequences out prevented the embryo from dividing past the 4 or 8 cell stage.

  4. 4
    gpuccio says:

    It could be interesting to remember that the genes usually called “oncogenes” were first discovered as viral genes which induced cancer in animals, while it was found, after some time, that they are really important genes (proto-oncogenes) regulating the cell cycle in animals, and that only when they are mutated or hyper-expressed do they cause cancer.

    Our understanding is often limited, until we get the right perspective.

  5. 5
    Mapou says:

    These findings should not be seen as evidence for Darwinian evolution. On the contrary, I think it strongly supports intelligent design. The designers simply have a huge database of unique genes and code sequences that they can use and reuse to design any living organism they desire: viruses, plants, mammals, birds, invertebrates, insects, etc. As simple as that.

  6. 6
  7. 7
    gpuccio says:

    Mung:

    Why the link?

  8. 8
    Mung says:

    You mentioned oncogenes and cancer and that brought to my mind oncology. That’s about it. 🙂

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