Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

First study hints at insights to come from genes unique to humans

25.03.2008
Among the approximately 23,000 genes found in human DNA, scientists currently estimate that there may be as few as 50 to 100 that have no counterparts in other species. Expand that comparison to include the primate family known as hominoids, and there may be several hundred unique genes.

Despite the distinctive contributions these genes likely make to our species, little is known about the roles they play. Now scientists at Washington University School of Medicine in St. Louis have produced the first detailed analysis of the cellular functions of a hominoid-only gene, TBC1D3. They affirmed earlier evidence linking the gene to cancer, showing that TBC1D3's protein can keep cellular growth factors active and helps turn on RAS, a protein that is active in a third of all human cancers.

"I was astounded at how little attention has been given to human-specific genes, which make us what we are and could potentially offer a great deal of insight into human physiology," says senior author Philip D. Stahl, Ph.D., the Edward Mallinckrodt Jr. Professor and head of Cell Biology and Physiology. "In addition, certain pathogens, such as the malaria parasite, have human specific-components in their infection cycle. Human-only genes could offer us unique insights into how the parasites take advantage of us and possibly provide potent new avenues for fighting back."

The paper appears online in The Journal of Biological Chemistry.

... more about:
»Active »Insight »TBC1D3 »effect »factor »function »paralog »receptor »unique

When scientists want to learn more about the function of a gene, they frequently disable or delete the gene in a laboratory animal and then look to see how the loss changes the animal. That won't be possible with genes unique to humans, Stahl notes. Researchers will have to resort to altering the genes' functions in human cell lines, or transplanting them into animals to see what effects they have.

TBC1D3 was originally identified by other scientists as a likely contributor to breast cancer. At the time of its discovery, researchers linked its protein to endocytosis, a process cells use to take in material from their surface.

Endocytosis plays an important role in the Stahl laboratory. His group studies how growth factor receptors, proteins important for both normal and cancerous growth, are turned on and off. Found on the surfaces of cells, growth factor receptors turn on when they bind to a growth factor protein. To turn them off, cells take in the combined receptor-protein through endocytosis and put it through a number of different processes before finally breaking down the growth factor receptor.

When Stahl and colleagues determined in 2006 that the TBC1D3 gene is only found in hominoids, their curiosity was piqued. Evolution, Stahl notes, naturally tends to retain genes involved in the most important components of metabolism. If one of these genes mutated too dramatically, that would lead to an organism so sickly that it wouldn't survive long enough to perpetuate the mutation in its descendants. So evolution "conserves" these genes, retaining them largely unchanged as one species evolves into another.

Therefore, if the genome is compared to an automobile, human-only genes are unlikely to be adding new wheels. But they could, for example, be contributing a new anti-lock braking system: a regulatory function that fine-tunes essential processes originally established millennia ago in other species.

Stahl found evidence that this is the case in TBC1D3. Human DNA has eight copies or paralogs of the TBC1D3 gene. His lab showed that the increased levels of the protein made by one of the paralogs makes human cells grow more rapidly. When they transplanted the gene for the protein into mouse cells, it had the same effect.

A closer look showed that the protein from the TBC1D3 paralog delays a process that labels growth factor receptors for breakdown, prolonging the time that their signal is active.

He also found evidence that the protein was helping to activate RAS, another gene whose protein is commonly found in human cancers.

Stahl and his colleagues plan additional research to learn whether the other paralogs of TBC1D3 have different roles. He also has several ideas for learning more about the functions of human-only genes.

"We might try an organ-by-organ approach, looking to see if any genes specific to a particular organs, such as fat, are specific to humans," he says. "We also should probably look at crystallizing the proteins from some of these genes, which can tell us more about what they interact with."

There may be human diseases where these genes are mutated or missing, Stahl speculates. The effects of such conditions could provide important clues to what the humans-only genes do.

"It's also going to be very interesting for evolutionary biologists to try to develop a sense for where these humans-only genes come from," Stahl says. "The building blocks of these genes may be present but not active in earlier species."

Michael Purdy | EurekAlert!
Further information:
http://www.wustl.edu

Further reports about: Active Insight TBC1D3 effect factor function paralog receptor unique

More articles from Life Sciences:

nachricht Immune Defense Without Collateral Damage
23.01.2017 | Universität Basel

nachricht The interactome of infected neural cells reveals new therapeutic targets for Zika
23.01.2017 | D'Or Institute for Research and Education

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Tracking movement of immune cells identifies key first steps in inflammatory arthritis

23.01.2017 | Health and Medicine

Electrocatalysis can advance green transition

23.01.2017 | Physics and Astronomy

New technology for mass-production of complex molded composite components

23.01.2017 | Process Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>