Scientists identify gene involved in stem cell self-renewal in planaria

Aug 07, 2006
Scientists identify gene involved in stem cell self-renewal in planaria
New research has identified a protein, produced by a gene found in both planarians and humans, that plays a vital role in maintaining the stem cell population in planarian. Phillip A. Newmark, U. of I. professor of cell and developmental biology, and graduate student Tingxia Guo were the Illinois co-authors of the paper to appear in the August issue of the journal Developmental Cell. Photo by L. Brian Stauffer

No matter how you slice it, the freshwater planarian possesses an amazing ability to regenerate lost body parts. Chop one into pieces, and each piece can grow into a complete planarian. The flatworm relies upon a population of stem cells to accomplish this remarkable feat; recent work sheds light on how planarians maintain these stem cells throughout their lives.

In a paper to appear in the August issue of the journal Developmental Cell, scientists show that a member of the Bruno-like family of RNA binding proteins – produced by a gene found in both planarians and humans – plays a vital role in maintaining the stem cell population in the planarian Schmidtea mediterranea. The work could lead to a better understanding of the fundamental mechanisms by which stem cells are regulated; such basic understanding is required for the successful therapeutic application of stem cells in humans.

“One of the defining characteristics of stem cells is their ability to self-renew – that is, to make more stem cells in addition to differentiating into multiple cell types,” said Phillip A. Newmark, a professor of cell and developmental biology at the University of Illinois at Urbana-Champaign and corresponding author of the paper. “We found that in the absence of this protein, the stem cells could respond to wound stimuli, proliferate, and differentiate, but they were unable to self-renew. As a result, the regeneration process failed and the animals died.”

Using a technique called RNA interference, Illinois graduate student Tingxia Guo and Newmark first eliminated most of the Bruno-like protein (Bruli) from a number of planarians. Then they amputated a small piece from each flatworm.

In the usual manner, the planarian stem cells migrated to the site of the wound, sensed what was missing and began rebuilding. Regeneration ceased, however, when the stem cell population became depleted.

“Had Bruli protein been present, the regeneration process would have continued to completion,” Newmark said. “What may be happening is that when this protein is eliminated, RNAs that are supposed to be turned off (that is, not made into proteins) are now turned on and made into proteins. Those proteins may then cause the stem cells to differentiate, instead of also producing new stem cells to maintain the population.”

While there is still much to be learned about stem cell self-renewal, the researchers’ results suggest that Bruli protein is required for stem cell maintenance in planarians.

“The next steps are to see if the gene that makes this protein in planarians plays a similar role in stem cells in other organisms and to identify possible RNA targets of this protein,” Newmark said.

Source: University of Illinois at Urbana-Champaign

Explore further: Merck completes sale of consumer unit to Bayer

add to favorites email to friend print save as pdf

Related Stories

Stem cells use 'first aid kits' to repair damage

Sep 18, 2014

Stem cells hold great promise as a means of repairing cells in conditions such as multiple sclerosis, stroke or injuries of the spinal cord because they have the ability to develop into almost any cell type. ...

Recommended for you

Merck completes sale of consumer unit to Bayer

4 minutes ago

Drugmaker Merck said Wednesday that it completed the sale of its consumer care business, which makes products including Claritin allergy medication and Coppertone sun-care line, to German health care company Bayer for $14.2 ...

First US child dies from enterovirus D68

14 minutes ago

A child in the northeastern US state of Rhode Island has become the first to die from an ongoing outbreak of a respiratory virus, enterovirus D68, health officials said Wednesday.

US Ebola patient had contact with kids: governor

24 minutes ago

A man who was diagnosed with Ebola in virus in Texas came in contact with young children, and experts are monitoring them for any signs of disease, governor Rick Perry said Wednesday.

UN worker dies of suspected Ebola in Liberia

50 minutes ago

The United Nations mission in Liberia announced on Wednesday the first suspected victim among its employees of the deadly Ebola epidemic ravaging the impoverished west African nation.

AAO-HNSF clinical practice guideline: Tinnitus

52 minutes ago

The American Academy of Otolaryngology—Head and Neck Surgery Foundation has released the first ever mutli-disciplinary, evidence-based clinical practice guideline to improve the diagnosis and management of tinnitus, the ...

User comments : 0