Featured Research

from universities, journals, and other organizations

Developmental bait and switch: Enzyme responsible for neural crest cell development discovered

Date:
November 2, 2012
Source:
California Institute of Technology
Summary:
During the early developmental stages of vertebrates, cells undergo extensive rearrangements, and some cells migrate over large distances to populate particular areas and assume novel roles as differentiated cell types. A new study provides new clues about this process -- at least in the case of neural crest cells, which give rise to most of the peripheral nervous system, to pigment cells, and to large portions of the facial skeleton.

A slice through an embryo showing neural cells (red), neural crest cells (blue), and blocking agent (green).
Credit: Image courtesy of California Institute of Technology

During the early developmental stages of vertebrates -- animals that have a backbone and spinal column, including humans -- cells undergo extensive rearrangements, and some cells migrate over large distances to populate particular areas and assume novel roles as differentiated cell types. Understanding how and when such cells switch their purpose in an embryo is an important and complex goal for developmental biologists. A recent study, led by researchers at the California Institute of Technology (Caltech), provides new clues about this process -- at least in the case of neural crest cells, which give rise to most of the peripheral nervous system, to pigment cells, and to large portions of the facial skeleton.

"There has been a long-standing mystery regarding why some cells in the developing embryo start out as part of the future central nervous system, but leave to populate peripheral parts of the body," says Marianne Bronner, the Albert Billings Ruddock Professor of Biology at Caltech and corresponding author of the paper, published in the November 1 issue of the journal Genes & Development. "In this paper, we find that an important type of enzyme called DNA-methyltransferase, or DNMT, acts as a switch, determining which cells will remain part of the central nervous system, and which will become neural crest cells."

According to Bronner, DNMT arranges this transition by silencing expression of the genes that promote central nervous system (CNS) identity, thereby giving the cells the green light to become neural crest, migrate, and do new things, like help build a jaw bone. The team came to this conclusion after analyzing the actions of one type of DNMT -- DNMT3A -- at different stages of development in a chicken embryo.

This is important, says Bronner, because while most scientists who study the function of DNMTs use embryonic stem cells that can be maintained in culture, her team is "studying events that occur in living embryos as opposed to cells grown under artificial conditions," she explains.

"It is somewhat counterintuitive that this kind of shutting off of genes is essential for promoting neural crest cell fate," she says. "Embryonic development often involves switches in the types of inputs that a cell receives. This is an example of a case where a negative factor must be turned off -- essentially a double negative -- in order to achieve a positive outcome."

Bronner says it was also surprising to see that an enzyme like DNMT has such a specific function at a specific time. DNMTs are sometimes thought to act in every cell, she says, yet the researchers have discovered a function for this enzyme that is exquisitely controlled in space and time.

"It is amazing how an enzyme, at a given time point during development, can play such a specific role of making a key developmental decision within the embryo," says Na Hu, a graduate student in Bronner's lab and lead author of the paper. "Our findings can be applied to stem cell therapy, by giving clues about how to engineer other cell types or stem cells to become neural crest cells."

Bronner points out that their work relates to the discovery, which won a recent Nobel Prize in Medicine or Physiology, that it is possible to "reprogram" cells taken from adult tissue. These induced pluripotent stem (iPS) cells are similar to embryonic stem cells, and many investigators are attempting to define the conditions needed for them to differentiate into particular cell types, including neural crest derivatives.

"Our results showing that DNMT is important for converting CNS cells to neural crest cells will be useful in defining the steps needed to reprogram such iPS cells," she says. "The iPS cells may in turn be useful for repair in human diseases such as familial dysautonomia, a disease in which there is depletion of autonomic and sensory neurons that are neural crest-derived; for repair of jaw bones lost in osteonecrosis; and for many other potential treatments."

In the short term, the team will explore the notion that DNMT enzymes may have different functions in the embryo at different places and times. That's why the next step in their research, says Bronner, is to examine the later role of these enzymes in nervous-system development, like whether or not they effect the length of time during which the CNS is able to produce neural crest cells.

Additional authors on the paper, titled "DNA methyltransferase3A as a molecular switch mediating the neural tube-to-neural crest fate transition," are Pablo Strobl-Mazzulla from the Laboratorio de Biologνa del Desarrollo in Chascomϊs, Argentina, and Tatjana Sauka-Spengler from the Weatherall Institute of Molecular Medicine at the University of Oxford. The work was supported by the National Institutes of Health and the United States Public Health Service.


Story Source:

The above story is based on materials provided by California Institute of Technology. The original article was written by Katie Neith. Note: Materials may be edited for content and length.


Journal Reference:

  1. N. Hu, P. Strobl-Mazzulla, T. Sauka-Spengler, M. E. Bronner. DNA methyltransferase3A as a molecular switch mediating the neural tube-to-neural crest fate transition. Genes & Development, 2012; 26 (21): 2380 DOI: 10.1101/gad.198747.112

Cite This Page:

California Institute of Technology. "Developmental bait and switch: Enzyme responsible for neural crest cell development discovered." ScienceDaily. ScienceDaily, 2 November 2012. <www.sciencedaily.com/releases/2012/11/121102115437.htm>.
California Institute of Technology. (2012, November 2). Developmental bait and switch: Enzyme responsible for neural crest cell development discovered. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2012/11/121102115437.htm
California Institute of Technology. "Developmental bait and switch: Enzyme responsible for neural crest cell development discovered." ScienceDaily. www.sciencedaily.com/releases/2012/11/121102115437.htm (accessed September 30, 2014).

Share This



More Plants & Animals News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

California University Designs Sustainable Winery

California University Designs Sustainable Winery

Reuters - US Online Video (Sep. 27, 2014) — Amid California's worst drought in decades, scientists at UC Davis design a sustainable winery that includes a water recycling system. Vanessa Johnston reports. Video provided by Reuters
Powered by NewsLook.com
Argentina Worries Over Decline of Soybean Prices

Argentina Worries Over Decline of Soybean Prices

AFP (Sep. 27, 2014) — The drop in price of soy on the international market is a cause for concern in Argentina, as soybean exports are a major source of income for Latin America's third largest economy. Duration: 01:10 Video provided by AFP
Powered by NewsLook.com
Mama Bear, Cubs Hang out in California Backyard

Mama Bear, Cubs Hang out in California Backyard

Reuters - US Online Video (Sep. 27, 2014) — A mama bear and her two cubs climb trees, wrestle and take naps in the backyard of a Monrovia, California home. Vanessa Johnston reports. Video provided by Reuters
Powered by NewsLook.com
'Crazy' Climate Forces Colombian Farmers to Adapt

'Crazy' Climate Forces Colombian Farmers to Adapt

AFP (Sep. 26, 2014) — Once upon a time, farming was a blissfully low-tech business on Colombia's northern plains. Duration: 02:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins