One hundred and fifty years ago, Dmitri Mendeleev created the periodic table, a system for classifying atoms based on the properties of the nucleus. This week, a team of biologists studying the tree of life revealed a new classification system for cell nuclei and discovered a way to transmit the nucleus of one cell type to another.
The study, which appears this week in the journal scienceCaused by several separate attempts One of them is centered on DNA Zoo, an international consortium comprising dozens of institutions including Baylor College of Medicine, National Science Foundation-Support Center for Theoretical Biological Physics (CTBP) at Rice University, University of Western Australia. And SeaWorld
Scientists in the DNA Zoo team have worked together to classify how long chromosomes, several meters long, fold up to fit in the nuclei of different organisms from across the tree of life.
“Whether we’re looking at worms or sea urchins or corals, we still see the same folding patterns,” said Dr. Olga Dudchenko, first co-author of the new study and a member of the Center for Genome Architecture, Baylor and CTBP.
Finally, the team realized it was just a glimpse of two different types of overall nuclear design. “In some species, chromosomes are newspaper-like, with an outer edge on one side and a center fold on the other,” explains Dudchenko, co-director of DNA Zoo. Each one is crumpled into a small ball. “
“So we have a mystery,” said Dr. Eres Lieberman Aiden, associate professor of molecular and human genetics and Baylor’s Emeritus McNair Scholar, co-director of DNA Zoo and senior author on the new study. “The data implies that during evolution, species can switch from one species to another. We wondered: What is a control mechanism? Is it possible to convert one type of nucleus to another in another type of nucleus?” The Laboratory, “Aiden is also director of the Center for Genome Architecture and a senior researcher at CTBP.
Meanwhile, an independent team in the Netherlands made an unexpected discovery. “I am conducting experiments on a protein called condensin II, which we know plays a role in cell division,” said Claire Hoencamp, co-first author of the study and a lab member of Dr. Hohmann. “But we noticed the strangest thing is that when we mutate a protein in human cells, the chromosomes are rearranged entirely. It’s puzzling!”
The two teams met at a conference in the Austrian mountains, where Rowland presented his laboratory’s latest work. They soon learned that Hoencamp had attacked a way to convert human cells from one type of nuclear to another.
“When we looked at the genome being studied at the DNA Zoo, we found that evolution has been doing our experiments many times before! When mutations in organisms destroy condensin II, they tend to overturn the entire structure of the nucleus, ”Rowland said. Senior author on the study “It is a little disappointing to benefit from the trials. But evolution had a very long start. “
The team decided to work together to confirm the role of condensin II, but then the COVID-19 epidemic happened and most of the world shut down.
“Without access to our lab, we are left with only one way to determine what condensin II is doing,” Hoencamp said. Hundreds of millions of chains of genetic letters that comprise each human chromosome.
The team turned to Dr. José Onuchic, Harry C., and Olga K. Wiess Chair of Physics at Rice. It looks like a flying nucleus, ”said Onuchik, co-director of CTBP, which includes collaborators at Rice, Baylor, Northeastern University and other institutions in Houston and Boston.
The simulation was performed by an in-house team of Onuchic at CTBP, led by Dr. Sumita Bhomchari, postdoctoral co-author and first co-author, who worked with Dr. Vinisius Contessoto, former postdoc at CTBP and researcher Dr. and now assistant professor at Northeastern University.
“We started with an incredibly broad exploration of over 2 billion years of nuclear evolution,” said Promma Shari. “And we’ve found that one simple mechanism allows us to simulate and deduce it ourselves in vitro – an exciting step on the path to new genome engineering in 3D! ”
Ring-shaped protein complexes cause DNA controversy.
“The 3D genomics across the tree of life reveal Condensin II determines the architectural genre.” science (2021) .sciencemag.org/cgi/doi … 1126 / science.abe2218
Provided by Baylor College of Medicine
Reference: Biologists create a ‘periodic table’ for cell nuclei (2021, May 27) .Retrieved May 28, 2021 from https://phys.org/news/2021-05-biologists-periodic-table-cell-nuclei.html.
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