Featured Research

from universities, journals, and other organizations

Gene family found to play key role in early stages of development

Date:
February 1, 2010
Source:
University of California - San Francisco
Summary:
Scientists have identified a gene family that plays a key role in one of the earliest stages of development in which an embryo distinguishes its left side from the right and determines how organs should be positioned within the body. The finding in mice likely will lead to a better understanding of how certain birth defects occur in humans.

Scientists have identified a gene family that plays a key role in one of the earliest stages of development in which an embryo distinguishes its left side from the right and determines how organs should be positioned within the body. The finding in mice likely will lead to a better understanding of how certain birth defects occur in humans.

The study is published in the January 24, 2010, advance online issue of the journal Nature Cell Biology.

"Having clear knowledge of embryonic development and how certain developmental processes can go awry is imperative for understanding the causes of the various types of human birth defects, which may eventually help us devise ways to correct those defects," said Anthony Wynshaw-Boris, MD, PhD, chief of medical genetics at UCSF Children's Hospital and a co-senior author of the study.

In the current study, the research team built upon previous work that uncovered the mechanism within the embryo responsible for specifying its left and right sides -- a process called left-right symmetry breaking. That research, conducted by geneticist Hiroshi Hamada, MD, PhD, and colleagues at Japan's Osaka University, showed how tail-like projections known as cilia located on the surface of cells in an embryonic region called the node generate a leftward flow of fluid outside the embryo, which, in turn, lets the embryo know which side is the left.

In this earlier work, Hamada's group discovered that the cilia are able to produce a leftward flow of fluid because they are located toward the back of the node cells and are tilted toward the embryo's tail end. This unique placement, coupled with the cilia's clockwise circular beating motion, results in the leftward flow and, subsequently, the embryo's left-right symmetry breaking. According to the researchers, if this directional flow is not established, organisms can develop with their internal organs on the wrong side of the body, decreasing chances for survival.

"Knowing that the cilia's placement on the node is intricately involved with this key stage of embryonic development, we decided to take our work a step further to see whether certain genes might determine how cilia retain this tilted position," said Hamada, who is also a co-senior author of the current study.

Hamada and Wynshaw-Boris decided to look at whether a specific gene family, called the "Dishevelled" gene family, might be directing the cilia's migration to the back side of the node cells. Having researched this gene family for many years, the Wynshaw-Boris lab developed mouse models with each of the three Dishevelled genes "turned off" to study their individual functions. In doing so, they found that the Dishevelled genes activate a genetic pathway, called the planar cell polarity pathway, which helps determine positional information in cells and tissues.

"We focused on the Dishevelled gene family because from our previous work, we knew that these genes were involved in the development of hair cells within the inner ear of the embryo, and that the cilia-like structures at the edge of the hair cells behave in a similar fashion as those on the node of the embryo. That similarity made us take a closer look at how this gene family was acting on correct placement of the nodal cilia at this very early stage of development," Wynshaw-Boris explained.

Masakazu Hashimoto, a graduate student in the Hamada lab and the first author of the study, monitored the movement of cilia in live mouse embryos using a high-speed camera attached to a microscope and observed that the cilia's position actually changed as development proceeded. In the very earliest stages -- before left-right symmetry breaking occurred -- cilia were located in the center of the node cells; then, as development progressed, the cilia gradually moved to the back side of the cells.

The researchers compared cilia in normal mouse embryos to those in embryos with mutated versions of all three Dishevelled genes. They found that the cilia in the mutant embryos were misplaced on the node cells and therefore unable to produce a leftward flow of fluid.

"This discovery provides exciting information about how we are built the way we are at the most basic of levels: that is, how do we differentiate our left side from our right? Ultimately this determines how the heart ends up on the left side of the body and the liver on the right side, for example," Wynshaw-Boris added.

Additional co-authors include Kyosuke Shinohara, Shingo Ikeuchi, Satoko Yoshiba, and Chikara Meno, all of Osaka University's Developmental Genetics Group; Jianbo Wang of the University of California, San Diego, Department of Pediatrics and Medicine; Shigenori Nonaka of Japan's National Institute for Basic Biology; Shinji Takada of the Okazaki Institute for Integrative Biosciences; and Kohei Hatta of the University of Hyogo Graduate School of Life Science.

The research was supported by a grant from Core Research for Evolutional Science and Technology of the Japan Science and Technology Corporation and a grant-in-aid from the Ministry of Education, Culture, Sports, Science, and Technology of Japan, as well as grants from the National Institutes of Health and March of Dimes.


Story Source:

The above story is based on materials provided by University of California - San Francisco. Note: Materials may be edited for content and length.


Journal Reference:

  1. Masakazu Hashimoto, Kyosuke Shinohara, Jianbo Wang, Shingo Ikeuchi, Satoko Yoshiba, Chikara Meno, Shigenori Nonaka, Shinji Takada, Kohei Hatta, Anthony Wynshaw-Boris & Hiroshi Hamada. Planar polarization of node cells determines the rotational axis of node cilia. Nature Cell Biology, 2010; DOI: 10.1038/ncb2020

Cite This Page:

University of California - San Francisco. "Gene family found to play key role in early stages of development." ScienceDaily. ScienceDaily, 1 February 2010. <www.sciencedaily.com/releases/2010/01/100125173454.htm>.
University of California - San Francisco. (2010, February 1). Gene family found to play key role in early stages of development. ScienceDaily. Retrieved April 18, 2014 from www.sciencedaily.com/releases/2010/01/100125173454.htm
University of California - San Francisco. "Gene family found to play key role in early stages of development." ScienceDaily. www.sciencedaily.com/releases/2010/01/100125173454.htm (accessed April 18, 2014).

Share This



More Health & Medicine News

Friday, April 18, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Obama: 8 Million Healthcare Signups

Obama: 8 Million Healthcare Signups

AP (Apr. 17, 2014) President Barack Obama gave a briefing Thursday announcing 8 million people have signed up under the Affordable Care Act. He blasted continued Republican efforts to repeal the law. (April 17) Video provided by AP
Powered by NewsLook.com
Is Apathy A Sign Of A Shrinking Brain?

Is Apathy A Sign Of A Shrinking Brain?

Newsy (Apr. 17, 2014) A recent study links apathetic feelings to a smaller brain. Researchers say the results indicate a need for apathy screening for at-risk seniors. Video provided by Newsy
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. Video provided by Newsy
Powered by NewsLook.com
Thousands Of Vials Of SARS Virus Go Missing

Thousands Of Vials Of SARS Virus Go Missing

Newsy (Apr. 16, 2014) A research institute in Paris somehow misplaced more than 2,000 vials of the deadly SARS virus. Video provided by Newsy
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:
from the past week

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