Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Transcription Factors Guide Differences in Human and Chimp Brain Function

08.12.2009
Humans share at least 97 percent of their genes with chimpanzees, but, as a new study of transcription factors makes clear, what you have in your genome may be less important than how you use it.

The study, in Proceedings of the National Academy of Sciences, found that broad differences in the gene activity of humans and of chimpanzees, affecting nearly 1,000 genes, appear to be linked to the action of about 90 transcription factors.

Transcription factors are proteins that bind to specific regions of the DNA to promote or repress the activity of many genes. A single transcription factor can spur the transcription of dozens of genes into messenger RNA (mRNA), which is then translated into proteins that do the work of the cell. This allows specific organs or tissues to quickly ramp up a response to an environmental change or internal need.

Previous studies have found differences in gene expression between humans and chimps, particularly in the brain. Genes involved in metabolism or protein transport, for example, are translated into mRNAs at a much higher level in human brains than in the smaller brains of chimpanzees.

This makes sense, said University of Illinois cell and developmental biology professor Lisa Stubbs, who led the new analysis with postdoctoral researcher Katja Nowick.

“These differences fit what we know because the human brain is so much larger and proteins need to be shuttled a long way out to the synapses,” Stubbs said. “A higher requirement for metabolic energy has also been demonstrated independently for human brains.”

What wasn’t clear from previous studies was how this upsurge in gene activity was coordinated, she said.

Stubbs has had a longtime interest in the evolutionary role of transcription factors and other regulatory agents in the genome. She is particularly interested in the largest family of transcription factors in mammals, the KRAB zinc finger (KRAB-ZNF) genes, which on average have accumulated more differences in sequence between humans and chimps than other genes.

“There are a lot of unique new transcription factors that arise in this family,” Stubbs said. “And they arise by duplication of older genes. So the genes make a new copy of themselves and then that new copy takes on a slightly different or even dramatically different function.”

“Our very strong bias is to believe that these transcription factors are involved in speciation and traits that make species unique,” she said.

Nowick, who studies human and primate evolution, was part of a team (at the Max Planck Institute for Evolutionary Anthropology, in Leipzig, Germany) that analyzed differences in gene expression between humans and chimps.

In the new study, Nowick and computer scientist Tim Gernat, a co-author, took a new look at data from that study, which tracked gene expression – including genes coding for transcription factors – in tissues from six humans and five chimpanzees.

“Katja and Tim came up with a strategy for cleaning up the data and looking at these genes more uniquely,” Stubbs said. “It hadn’t been done before.”

The analysis revealed a broad pattern of activity in 90 transcription factors that paralleled the activity of about 1,000 genes in humans and chimps.

The KRAB-ZNF genes were the most common members of this group, but many other transcription factors were also involved. Some were activators and some were repressors, but their activity coincided with a general upsurge of these genes in human brains.

Eivind Almaas, a researcher at the Norwegian University of Science and Technology and a co-author on the study, developed a gene regulatory network diagram of the transcription factors in relation to the genes that rise or fall with them. The proximity of one transcription factor to another in the network depended on the degree of overlap of the lists of genes that correlate with each. Almaas created one network diagram for humans and another for chimps, and uncovered some interesting differences.

“The chimp network looks very much like the human one except there are a few transcription factors in different positions and with different connectivity,” Stubbs said. “Those are of interest from the point of view that they signal a major gene regulatory shift between species, and this shift may help us explain some of the biological differences.”

The new findings indicate that certain transcription factors are working together in a coordinated way to regulate the changes in seen in gene expression between humans and chimps, the researchers said.

“Once this network of transcription factors is established, changes in the network can be amplified because transcription factors control other genes,” Nowick said. “Even a small change in transcription factor expression can therefore produce a large effect on overall gene expression differences between chimpanzees and humans.”

Diana Yates | University of Illinois
Further information:
http://www.illinois.edu

More articles from Life Sciences:

nachricht One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

nachricht The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>