In:
eLife, eLife Sciences Publications, Ltd, Vol. 1 ( 2012-11-13)
Abstract:
Embryonic stem cells have two characteristic properties: they are able to differentiate into any type of cell, a property known as pluripotency, and they are able to replicate themselves indefinitely to produce an endless supply of new stem cells. Different genes code for the various proteins associated with these two properties, and understanding the behaviour and properties of stem cells in detail is a major challenge in developmental biology. In human embryonic stem cells that have not yet differentiated, the genes that code for the transcription factors involved in the self-renewal process are expressed, whereas the genes associated with differentiation are not active. However, if the expression of the genes for self-renewal is reduced, the process of differentiation will begin, and the embryonic stem cells will be able to produce any one of the 200 or so different types of cell found in the human body. All of this activity is orchestrated by proteins that oversee the transcription of specific regions of DNA into messenger RNA. Transcription is the first step in the process by which genes are expressed as proteins, and it cannot start until the relevant transcription factor binds to a stretch of DNA near the gene called the promoter. These transcription factors are complex structures that contain a central protein called TBP, which binds to the promoter, and 14 or so other proteins called TAFs. Maston et al. now report that the transcription machinery that regulates gene expression and self-renewal in human embryonic stem cells is different from that found in other types of cells, including embryonic stem cells taken from mice. In particular, they found that undifferentiated human embryonic stem cells contain only 6 of the 14 TAFs observed in other cells, although all 14 are present after differentiation. Moreover, for many active genes the transcription factors contained only two of these TAFs. There was also evidence for a new complex that contained the other four TAFs plus TBP. Maston et al. also demonstrated that the removal of just one of the six TAFs, or the addition of just one extra TAF, caused the process of differentiation to begin. This shows, they argue, that the unusual transcription machinery they have discovered is essential for the proper workings of human embryonic stem cells.
Type of Medium:
Online Resource
ISSN:
2050-084X
DOI:
10.7554/eLife.00068.001
DOI:
10.7554/eLife.00068.002
DOI:
10.7554/eLife.00068.003
DOI:
10.7554/eLife.00068.004
DOI:
10.7554/eLife.00068.005
DOI:
10.7554/eLife.00068.006
DOI:
10.7554/eLife.00068.007
DOI:
10.7554/eLife.00068.008
DOI:
10.7554/eLife.00068.009
DOI:
10.7554/eLife.00068.010
DOI:
10.7554/eLife.00068.011
DOI:
10.7554/eLife.00068.012
DOI:
10.7554/eLife.00068.013
DOI:
10.7554/eLife.00068.014
DOI:
10.7554/eLife.00068.015
DOI:
10.7554/eLife.00068.016
DOI:
10.7554/eLife.00068.017
DOI:
10.7554/eLife.00068.018
DOI:
10.7554/eLife.00068.019
DOI:
10.7554/eLife.00068.020
DOI:
10.7554/eLife.00068.021
DOI:
10.7554/eLife.00068.022
DOI:
10.7554/eLife.00068.023
DOI:
10.7554/eLife.00068.024
DOI:
10.7554/eLife.00068.025
DOI:
10.7554/eLife.00068.026
DOI:
10.7554/eLife.00068.027
DOI:
10.7554/eLife.00068.028
Language:
English
Publisher:
eLife Sciences Publications, Ltd
Publication Date:
2012
detail.hit.zdb_id:
2687154-3