Marking of tissue-specific crucial in embryonic stem cells to ensure proper function

Dec 16, 2009

Tissue-specific genes, thought to be dormant or not marked for activation in embryonic stem cells, are indeed marked by transcription factors, with proper marking potentially crucial for the function of tissues derived from stem cells.

The finding in the study by researchers at the Broad Stem Cell Research Center involves a class of genes whose properties previously were thought to be unimportant for stem cell function. Most research has instead focused on genes that regulate a pluripotency network and genes that regulate differentiation of embryonic stem cells into other cell lineages.

The Broad center researchers focused on a third class of genes, those expressed only in defined cell types or tissues, which generally remain silent until long after embryonic stem cells have differentiated into specific cell lineages.

"Although prior models suggested that the cascade of events leading to the activation of tissue-specific genes doesn't begin until embryonic stem cells have differentiated, our findings support a new hypothesis in which the competence of these genes for expression is dependent on specific marks established in the pluripotent state," said Stephen Smale, a professor of microbiology, and and senior author of the study. "If this hypothesis is correct, the proper marking of tissue-specific genes may be essential for pluripotency and the efficient differentiation of stem cells into clinically usable cell types and tissues."

The study is published in the Dec. 15, 2009 issue of the peer-reviewed journal .

Prior to this study, typical tissue-specific genes were believed to have no critical interactions and exist in a base state in embryonic stem cells, sitting silently in the cell waiting to be "marked" by proteins that set in motion a cascade of molecular events. However, Smale and his team unexpectedly identified protein marks on these genes in stem cells and obtained striking evidence that the absence of these stem cell marks compromises gene expression in stem cell-derived tissues. The finding that these genes were already marked was surprising, Smale said.

"This finding may help us understand what it really means to be pluripotent," Smale said. "True may depend on faithful marking in pluripotent stem cells of many or all genes within the human genome."

This could be particularly important for those seeking to use or reprogrammed cells, called induced pluripotent stem (iPS) cells, to treat diseases or in regenerative medicine. The stem cell marks may ensure that the end result - a beta cell to treat diabetes, a neuron for Parkinson's disease, or a cardiac cell for heart problems - is a fully functional cell operating at 100 percent of its potential.

"We really do need to pay attention to these genes at the outset," Smale said. "Although silent in , their properties appear to be very important."

Explore further: Top Japan lab dismisses ground-breaking stem cell study

Provided by University of California - Los Angeles

5 /5 (1 vote)
add to favorites email to friend print save as pdf

Related Stories

Genes that control embryonic stem cell fate identified

Jul 10, 2008

Scientists have identified about two dozen genes that control embryonic stem cell fate. The genes may either prod or restrain stem cells from drifting into a kind of limbo, they suspect. The limbo lies between the embryonic ...

Adult stem cells lack key pluripotency regulator

Oct 10, 2007

The protein Oct4 plays a major role in embryonic stem cells, acting as a master regulator of the genes that keep the cells in an undifferentiated state. Unsurprisingly, researchers studying adult stem cells have long suspected ...

Recommended for you

Top Japan lab dismisses ground-breaking stem cell study

Dec 26, 2014

Japan's top research institute on Friday hammered the final nail in the coffin of what was once billed as a ground-breaking stem cell study, dismissing it as flawed and saying the work could have been fabricated.

Research sheds light on what causes cells to divide

Dec 24, 2014

When a rapidly-growing cell divides into two smaller cells, what triggers the split? Is it the size the growing cell eventually reaches? Or is the real trigger the time period over which the cell keeps growing ...

Locking mechanism found for 'scissors' that cut DNA

Dec 24, 2014

Researchers at Johns Hopkins have discovered what keeps an enzyme from becoming overzealous in its clipping of DNA. Since controlled clipping is required for the production of specialized immune system proteins, ...

Scrapie could breach the species barrier

Dec 24, 2014

INRA scientists have shown for the first time that the pathogens responsible for scrapie in small ruminants (prions) have the potential to convert the human prion protein from a healthy state to a pathological ...

Extracting bioactive compounds from marine microalgae

Dec 24, 2014

Microalgae can produce high value health compounds like omega-3s , traditionally sourced from fish. With declining fish stocks, an alternative source is imperative. Published in the Pertanika Journal of Tr ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.