The developmental on-switch

Aug 19, 2013
The Pou5f1 protein acts as an on-switch for embryonic development in zebrafish. Credit: Wolfgang Driever

German researchers have demonstrated for the first time why the molecular cocktail responsible for generating stem cells works. Sox2 and Oct4 are proteins whose effect on cells resembles that of an eraser: They remove all of the cell's previous experiences and transform it into a so-called pluripotent stem cell. Like cells in the embryo, this stem cell can then develop into all forms of tissue. The discoverers of this reprogramming technique received the Nobel Prize in Physiology or Medicine in 2012. However, until now scientists did not understand precisely why these proteins can reprogram cells and what function they have in the embryo.

A team from the Department of Developmental Biology and the Cluster of Excellence BIOSS Centre for Biological Signalling Studies, led by Dr. Daria Onichtchouk and Prof. Dr. Wolfgang Driever, has discovered that the Oct4 protein in the zebrafish embryo, which is initially provided by the mother, is responsible for switching on the embryo's genes for the first time, thus initiating the animal's independent development. Young embryonic cells can develop into all tissues and cell types found in the body, just like cultures of the so-called pluripotent stem cells. These multi-talented cells are the focus of much attention in biomedical research because experts hope to use them to regenerate damaged organs without having to resort to .

In an article published in the journal Science, the Freiburg scientists explain that the zebrafish Pou5f1 protein, which is very similar to the human Oct4 protein, serves as the main starting signal for embryonic development. Pou5f1 awakens the genes after the resting period following fertilization. In all animals, development is initially controlled by proteins from the mother in the ; the genes of the embryo are not activated until some time later. In the zebrafish, for instance, this process is triggered as soon as the embryo has a thousand cells. This "zygotic " reprograms the cells of the embryo: Specialized, rapidly dividing cells that do not create any new gene products become stem cells. These embryo stem cells can form all cell types – like pluripotent stem cells. In the case of so-called mesodermal cells, which can form blood or muscles, the scientists demonstrate how the Pou5f1 protein sets off the cascade of gene products that create muscle, blood, or bone cells from the . This regulatory network is very similar to that of the pluripotent stem cells.

Researchers have been able to generate for several years now, but have found it difficult to convert them into stable cell types with sufficient reliability – if stem cells are unstable, they can become cancerous. Using the regulatory network discovered in the zebrafish, developmental biologists can now study how particular cell types in the body are created from stem cells and what makes them stable. Scientists require reliable processes for forming stable tissue before it can be used for applications in medicine.

Explore further: Researchers identify new mechanism to aid cells under stress

More information: Leichsenring, M. et al. Pou5f1 Transcription Factor Controls Zygotic Gene Activation In Vertebrates, Science (online in Science Express 15 August 2013). DOI: 10.1126/science.1242527

add to favorites email to friend print save as pdf

Related Stories

Tracking nanodiamond-tagged stem cells

Aug 05, 2013

A method that is used to track the fate of a single stem cell within mouse lung tissue is reported in a study published online this week in Nature Nanotechnology. The method may offer insights into the factors that determ ...

When cells are consumed by wanderlust

Jul 22, 2013

(Medical Xpress)—In experiments on zebrafish, Freiburg researchers have demonstrated that the same proteins that lead to the formation of metastases in humans also cause the cells to migrate during embryonic ...

Recommended for you

Researchers identify new mechanism to aid cells under stress

18 hours ago

A team of biologists from NYU and Harvard has identified new details in a cellular mechanism that serves as a defense against stress. The findings potentially offer insights into tumor progression and neurodegenerative diseases, ...

Researchers image and measure tubulin transport in cilia

19 hours ago

Defective cilia can lead to a host of diseases and conditions in the human body—from rare, inherited bone malformations to blindness, male infertility, kidney disease and obesity. Scientists knew that somehow ...

Researchers find unusually elastic protein

22 hours ago

Scientists at Heidelberg University have discovered an unusually elastic protein in one of the most ancient groups of animals, the over 600-million-year-old cnidarians. The protein is a part of the "weapons system" that the ...

How malaria-spreading mosquitoes can tell you're home

Jan 22, 2015

Females of the malaria-spreading mosquito tend to obtain their blood meals within human dwellings. Indeed, this mosquito, Anopheles gambiae, spends much of its adult life indoors where it is constantly expose ...

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.