Nav: Home

Differing duration of brain stem cell division

October 10, 2016

Our similarities and differences to chimpanzees, our great ape cousins, have intrigued people for centuries. Of particular interest is the brain. Scientists at the Max Planck Institute of Molecular Cell Biology and Genetics in Dresden and the Max Planck Institute for Evolutionary Anthropology in Leipzig now report the first detailed comparison of how human and chimpanzee stem cells form a cerebral cortex during brain development. They uncover a subtle but intriguing difference in how the cortical stem cells divide - the human cells take more time to arrange the chromosomes before they are distributed to the daughter cells. This may help to understand why human and chimpanzee brains develop differently.

The team of researchers from the groups of Wieland Huttner at the Max Planck Institute of Molecular Cell Biology and Genetics and Svante Pääbo and Barbara Treutlein at the Max Planck Institute for Evolutionary Anthropology first reprogrammed ape white blood cells to obtain induced pluripotent stem cells (iPSCs). Then they used these cells as well as human iPSCs to grow cerebral organoids, tissue structures that resemble developing brain tissue. The brain stem cells from ape and human organoids were very similar to each other in terms of the subtypes of stem cells formed, their gene expression, and how they divide.

Surprisingly, however, the duration of one phase of the cell division process, as revealed by imaging of brain stem cells in the living cerebral organoids, was different between humans, chimpanzees and orangutan. Specifically, the duration of metaphase, when the chromosomes line up before division, was around 50% longer in humans. "We think this difference could indicate that human brain stem cells have a higher proliferation capacity than those of chimpanzees. In brain stem cells that tend to proliferate, this phase was longer than in those that tend to generate neurons", says lead author Felipe Mora-Bermúdez who made these observations. The next step will be to investigate the link between metaphase length and brain stem cell proliferation vs. differentiation further.

The researchers also found that human cerebral organoids contain a higher proportion of proliferative cortical stem cells than chimpanzee organoids, and gene expression differences between the species also hinted that proliferation capacity differs between the species. "The subtle but intriguing differences we have found at the cellular and molecular level may play important roles in the evolution of the human brain", concludes Wieland Huttner, who supervised the study. The researchers will now focus on investigating the mechanisms and implications of these differences.
-end-
Original publication

Felipe Mora-Bermúdez, Farhath Badsha, Sabina Kanton, J. Gray Camp, Benjamin Vernot, Kathrin Köhler, Birger Voigt, Keisuke Okita, Tomislav Maricic, Zhisong He, Robert Lachmann, Svante Pääbo, Barbara Treutlein and Wieland B. Huttner
Differences and similarities between human and chimpanzee neural progenitors during cerebral cortex development.
eLife; 26 September, 2016
http://dx.doi.org/10.7554/eLife.18683

Max-Planck-Gesellschaft

Related Chromosomes Articles:

Andalusian experts indicate new elements responsible for instability in chromosomes
The researchers state that RNA joins with DNA by chance or because of a disease, the structure of the chromatin, the protein envelope of the chromosomes is altered, causing breaks in the DNA.
Reconstruction of ancient chromosomes offers insight into mammalian evolution
Researchers have gone back in time, at least virtually, computationally recreating the chromosomes of the first eutherian mammal, the long-extinct, shrewlike ancestor of all placental mammals.
Newly discovered DNA sequences can protect chromosomes in rotifers
Rotifers are tough, microscopic organisms highly resistant to radiation and repeated cycles of dehydration and rehydration.
For keeping X chromosomes active, chromosome 19 marks the spot
After nearly 40 years of searching, Johns Hopkins researchers report they have identified a part of the human genome that appears to block an RNA responsible for keeping only a single X chromosome active when new female embryos are formed, effectively allowing for the generally lethal activation of more than one X chromosome during development.
Researchers assemble five new synthetic chromosomes
A global research team has built five new synthetic yeast chromosomes, meaning that 30 percent of a key organism's genetic material has now been swapped out for engineered replacements.
Jumbled chromosomes may dampen the immune response to tumors
How well a tumor responds to immunotherapy may depend in part on whether its chromosomes are intact or in a state of disarray, a new study reports.
Aging and cancer: An enzyme protects chromosomes from oxidative damage
EPFL scientists have identified a protein that caps chromosomes during cell division and protect them from oxidative damage and shortening, which are associated with aging and cancer.
Protective barrier inside chromosomes helps to keep cells healthy
Fresh insights into the structures that contain our genetic material could explain how the body's cells stay healthy.
How human eggs end up with the wrong number of chromosomes
One day before ovulation, human oocytes begin to divide into what will become mature eggs.
Genes versus chromosomes: A battle for expression in fly testes
Unique sex chromosomes occur in many species. An unequal pair of sex chromosomes, each carrying a different complement of genes, requires specific efforts to regulate and balance the expression of sex-chromosomal genes.

Related Chromosomes Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Setbacks
Failure can feel lonely and final. But can we learn from failure, even reframe it, to feel more like a temporary setback? This hour, TED speakers on changing a crushing defeat into a stepping stone. Guests include entrepreneur Leticia Gasca, psychology professor Alison Ledgerwood, astronomer Phil Plait, former professional athlete Charly Haversat, and UPS training manager Jon Bowers.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".