Nature Blog Network

Saturday, August 4, 2007

The Key to the Human Condition resides in a Platyhelminth

Schmidtea mediterranea, the holder of the key to regeneration. Photo from the Reddien Lab.

Not only are platyhelminths fantastic subjects for 8th grade science fair projects, but they also seem to have some useful biology that some researchers feel translates to Humans. Oviedo & Levin report in the journal Development on a newly discovered gene that regulates regeneration. Platyhelminths are wondrous worms when it comes to replacing a chopped off posterior or half-bitten head as described in a Nature news piece about the research,
"The flatworms, best known for their regenerative prowess and cross-eyed charm, maintain a supply of stem cells to regrow tissue lost to anything from daily wear-and-tear to full decapitation.
Sweet, "full decapitation". Now that is something to recover from!

Unfortunately, our library has an online only subscription to Development and they do not allow access to articles until 6 months after publication. Seems a bit counter-progressive, so I only have the Nature news piece and the abstract to go on. But what I find interesting about this research is that the gene they identified is gap junction channel gene found in adult stem cells of our wormy friend. These genes code for proteins that form a communications link between cells using small molecules. This is important for morphogenesis, suppression of tumor formation, and physiology. The study by Oviedo & Levin is the first study (according to the authors) to functionally link gap junction proteins to adult stem cells or organ regeneration. The authors knocked out the gap junction channel gene and observed that the platyhelminth lost the ability to regenerate as well as losing its reservoir of adult stem cells. In humans, knocking out the gap channel genes decreases embryonic stem cell proliferation. Oviedo & Levin conclude rather optimistically,
"Our data demonstrate a novel role for gap junction proteins and suggest gap junction-mediated signaling as a new and tractable control point for adult, somatic stem cell regulation."
It is still quite a jump from Platyhelminthes to a tiny taxon within the Chordata. Vertebrate gap junction channel proteins are a different group from the invertebrate gap proteins and show low sequence homology between the groups (see here).

Without being able to see the actual data, I can't really say more except that the 6-month rule is bogus and prevents other workers from citing your paper or building upon your results. It stymies science!

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