Navigation Links
The skeleton: Size matters
Date:10/27/2009

Vertebrates have in common a skeleton made of segments, the vertebrae. During development of the embryo, each segment is added in a time dependent manner, from the head-end to the tail-end: the first segments to be added become the vertebrae of the neck, later segments become the vertebrae with ribs and the last ones the vertebra located in the tail (in the case of a mouse, for example). In this process, it is crucial that, on the one hand, each segment, as it matures, becomes the correct type of vertebra and, on the other, that the number of vertebrae in the skeleton, and therefore the size of the spine, are minutely controlled.

It has long been known that the identity of each vertebra is due to the activation of a class of genes called Hox. Now, in the latest issue of Developmental Cell (*) researchers from the Instituto Gulbenkian de Cincia, in Portugal, the Institute KNAW and University Medical Centre (The Netherlands) show that besides determining the identity of the vertebrae, Hox genes also have a say in how many are going to be formed at all.

There is a huge diversity in number of vertebrae in animals: some have many vertebrae, and are thus longer, like a snake, and others have fewer vertebrae and are shorter, like mice. Vertebrae are made from precursors known as somites, formed in the embryos, sequentially from head to tail. This process is directly linked to growth of the embryo at its tail end: the more it grows, the more somites it makes and, as a result the more vertebrae the adult animal has. Of the many genes involved in this growth, a family of genes called Cdx are known to play a central role.

According to Moises Mallo, group leader at the IGC and one of the lead authors on the paper, 'We knew that some Hox genes are not activated when the Cdx genes are turned off, but this was always considered to be part of a mechanism to ensure that each new somite generates the appropriate type of vertebra. We now show that the activation of Hox genes is also part of how Cdx genes promote growth of the embryo at its tail end: when the relevant Hox genes were activated in the Cdx mouse mutants the embryos recovered and were born with a quite normal vertebral column, proving that the Hox genes were able to compensate for the lack of Cdx. This is a novel role for Hox genes'.

The researchers also show that some Hox genes are important to stop the addition of extra segments, at later stages in development. Indeed, if Hox genes that are usually active later on in development, in the last forming segments, are turned on before their time, in mouse embryos, they interrupt addition of new segments and lead to a tail truncation in the vertebral column.

As Mallo puts it, 'This paper provides and important addition to a long-standing view on the role of the Hox genes one of the most-studied genes involved in embryonic development: that it controls not only identity, but also number of vertebrae. Although these observations were made in the tail-end region of the embryo, it is very likely that similar mechanisms might be acting to determine the number of segments closer to the head".


'/>"/>

Contact: Silvia Castro
sacastro@igc.gulbenkian.pt
351-214-464-537
Instituto Gulbenkian de Ciencia
Source:Eurekalert

Related biology news :

1. Shape matters in the case of cobalt nanoparticles
2. Penn biologists demonstrate that size matters... in snail shells
3. Sequence matters in droughts and floods
4. In spiders, size matters: Small males are more often meals
5. How size matters
6. Primate sperm competition: speed matters
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/19/2016)... 20, 2016 The new GEZE ... compact web-based "all-in-one" system solution for all door components. ... or the door interface with integration authorization management system, ... systems. The minimal dimensions of the access control and ... building installations offer considerable freedom of design with regard ...
(Date:4/13/2016)... CHICAGO , April 13, 2016  IMPOWER physicians ... are setting a new clinical standard in telehealth ... By leveraging the higi platform, IMPOWER patients can ... weight, pulse and body mass index, and, when they ... quick and convenient visit to a local retail location ...
(Date:3/23/2016)... Massachusetts , March 23, 2016 /PRNewswire/ ... im Interesse erhöhter Sicherheit Gesichts- und Stimmerkennung ... Xura, Inc. (NASDAQ: MESG ), ... bekannt, dass das Unternehmen mit SpeechPro zusammenarbeitet, ... aus der Finanzdienstleistungsbranche, wird die Möglichkeit angeboten, ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... , ... June 27, 2016 , ... ... their findings on what they believe could be a new and helpful biomarker ... new research. Click here to read it now. , Biomarkers are ...
(Date:6/27/2016)... ... June 27, 2016 , ... Rolf K. Hoffmann, former senior ... the University of North Carolina Kenan-Flagler Business School effective June 27. ... Kenan-Flagler, with a focus on the school’s international efforts, leading classes and participating ...
(Date:6/24/2016)... 2016  Regular discussions on a range of subjects including ... two entities said Poloz. Speaking at a lecture ... , he pointed to the country,s inflation target, which is ... "In certain areas there ... common economic goals, why not sit down and address strategy ...
(Date:6/24/2016)... ... 2016 , ... Researchers at the Universita Politecnica delle Marche in Ancona combed ... pleural mesothelioma. Their findings are the subject of a new article on the Surviving ... signposts in the blood, lung fluid or tissue of mesothelioma patients that can help ...
Breaking Biology Technology: