Unpacking condensins' function in embryonic stem cells

Feb 22, 2010
The nuclei of embryonic stem cells lacking Smc2 (right) are large and misshapen. Credit: Fazzio, T.G., and B. Panning. 2010. J. Cell Biol. doi:10.1083/jcb.200908026.

Regulatory proteins common to all eukaryotic cells can have additional, unique functions in embryonic stem (ES) cells, according to a study in the February 22 issue of the Journal of Cell Biology. If cancer progenitor cells—which function similarly to stem cells—are shown to rely on these regulatory proteins in the same way, it may be possible to target them therapeutically without harming healthy neighboring cells.

The new study, by Thomas Fazzio and Barbara Panning (University of California, San Francisco) finds that two chromatin regulatory proteins essential for ES cell survival, Smc2 and Smc4, together form the heart of the condensin complexes that promote chromosome condensation in mitosis and meiosis. Because somatic cells lacking condensins continue to proliferate with relatively minor mitotic defects, Fazzio and Panning wondered why ES cells died in the absence of Smc2 or Smc4.

ES cells lacking the condensin subunits accrued massive amounts of that resulted in cell death. It isn't clear why ES cells are so sensitive to the loss of condensins, but it may be connected to two other phenotypes seen in ES, but not somatic, cells. After Smc2 or Smc4 was blocked, mitotic ES cells arrested in metaphase and interphase ES were enlarged and misshapen.

This suggests that condensins promote mitotic progression and maintain interphase chromatin compaction in ES cells—functions that they don't have in . In fact, many other chromatin regulatory proteins involved in ES cell survival can be depleted in differentiated cells without affecting viability, indicating that the chromatin of ES cells—and possibly cancer progenitor cells—is fundamentally different from somatic cell chromatin.

Explore further: How plant cell compartments change with cell growth

More information: Fazzio, T.G., and B. Panning. 2010. J. Cell Biol. doi:10.1083/jcb.200908026

add to favorites email to friend print save as pdf

Related Stories

Novel molecular 'signature' marks DNA of embryonic stem cells

Apr 20, 2006

A team of scientists announced today a critical step on the path of realizing the promise of embryonic stem (ES) cells for medicine. As described in the April 21 issue of Cell, the researchers have discovered unique molecular ...

Molecular alliance that sustains embryonic stem cell state

Mar 04, 2008

One of the four ingredients in the genetic recipe that scientists in Japan and the U.S. followed last year to persuade human skin cells to revert to an embryonic stem cell state, is dispensable in ES cells, thanks to the ...

Recommended for you

How plant cell compartments change with cell growth

16 hours ago

A research team led by Kiminori Toyooka from the RIKEN Center for Sustainable Resource Science has developed a sophisticated microscopy technique that for the first time captures the detailed movement of ...

Plants can 'switch off' virus DNA

16 hours ago

A team of virologists and plant geneticists at Wageningen UR has demonstrated that when tomato plants contain Ty-1 resistance to the important Tomato yellow leaf curl virus (TYLCV), parts of the virus DNA ...

A better understanding of cell to cell communication

17 hours ago

Researchers of the ISREC Institute at the School of Life Sciences, EPFL, have deciphered the mechanism whereby some microRNAs are retained in the cell while others are secreted and delivered to neighboring ...

A glimpse at the rings that make cell division possible

17 hours ago

Forming like a blown smoke ring does, a "contractile ring" similar to a tiny muscle pinches yeast cells in two. The division of cells makes life possible, but the actual mechanics of this fundamental process ...

User comments : 0