Nav: Home

GPS for chromosomes: Reorganization of the genome during development

February 28, 2020

The spatial arrangement of genetic material within the cell nucleus plays an important role in the development of an organism. A research team from the University of Basel, in collaboration with scientists from Harvard University, has developed a method to trace the chromosomes in individual cells. Using this method, they have now been able to demonstrate that chromosomes reorganize during embryonic development. The study has recently been published in Molecular Cell.

Our body is made up of a wide variety of cells with the most diverse functions. Irrespective of being heart, liver or nerve cells, however, they all contain the same genetic information. The reason why cells develop differently is that only parts of their chromosomes are read. This results in some genes being active while others, in contrast, are silent.

For gene activation, both the way the genes are packaged as well as their spatial organization in the cell nucleus play a decisive role. Prof. Susan Mango's team at the Biozentrum of the University of Basel has now investigated this 3D architecture more closely. Using a novel technique, they were able to trace individual chromosomes during embryonic development in nematodes and show that they rearrange themselves during the early phase.

Chromosome arrangement is not random

If stretched out, all the DNA molecules of a cell would reach about two meters in length. So the DNA must be densely packed to fit into a cell nucleus of only few micrometers in size. The DNA strands are very tightly coiled and twisted to form space-saving structures, called chromosomes. The packaging and the arrangement of the DNA of the chromosomes determines the activity of genes.

In their study, the researchers led by Prof. Susan Mango traced individual chromosomes and investigated their organization during early embryonic development. Embryonic cells of the nematode C. elegans served as a model. "Using a novel technique, we were able to follow the spatial rearrangement of chromosomes in single cells at the beginning of embryogenesis," says Mango. "The advantage of this method is that the cells and tissue remain completely intact."

Early chromosomes resemble a barbell

It is well know that chromosome regions with similar functional properties contact each other and interact. This means that chromosome domains segregated into two compartments, active and inactive. "During early embryogenesis, however, the chromosomes are organized differently," says Ahilya Sawh, first author of the study. "In the early embryo, they are organized into an unconventional barbell-like structure, with inactive compartments separated by a central active region." The researchers discovered that the nuclear lamina - a protein mesh lining the inner surface of the cell nucleus - is required to achieve this barbell arrangement. The lamina is attached to the inactive sections and stretches the chromosome.

Chromosomes reorganize during embryogenesis

"Only at a later stage of embryonic development, when the germ layers develop, we actually see the well-known segregation into an active and inactive region," explains Mango. "Using chromosome tracing, we were able to map the whole 3D chromosome architecture and could show for the first time that chromosomes rearrange during early development, a maturation process that requires the nuclear lamina."

The reorganization of the chromosomes accompanies cell maturation and represents a milestone in the development of a complex organism. The correct chromosomal architecture is crucial to prevent developmental disorders.

University of Basel

Related Dna Articles:

Zigzag DNA
How the cell organizes DNA into tightly packed chromosomes. Nature publication by Delft University of Technology and EMBL Heidelberg.
Scientists now know what DNA's chaperone looks like
Researchers have discovered the structure of the FACT protein -- a mysterious protein central to the functioning of DNA.
DNA is like everything else: it's not what you have, but how you use it
A new paradigm for reading out genetic information in DNA is described by Dr.
A new spin on DNA
For decades, researchers have chased ways to study biological machines.
From face to DNA: New method aims to improve match between DNA sample and face database
Predicting what someone's face looks like based on a DNA sample remains a hard nut to crack for science.
Self-healing DNA nanostructures
DNA assembled into nanostructures such as tubes and origami-inspired shapes could someday find applications ranging from DNA computers to nanomedicine.
DNA design that anyone can do
Researchers at MIT and Arizona State University have designed a computer program that allows users to translate any free-form drawing into a two-dimensional, nanoscale structure made of DNA.
DNA find
A Queensland University of Technology-led collaboration with University of Adelaide reveals that Australia's pint-sized banded hare-wallaby is the closest living relative of the giant short-faced kangaroos which roamed the continent for millions of years, but died out about 40,000 years ago.
DNA structure impacts rate and accuracy of DNA synthesis
DNA sequences with the potential to form unusual conformations, which are frequently associated with cancer and neurological diseases, can in fact slow down or speed up the DNA synthesis process and cause more or fewer sequencing errors.
Changes in mitochondrial DNA control how nuclear DNA mutations are expressed in cardiomyopathy
Differences in the DNA within the mitochondria, the energy-producing structures within cells, can determine the severity and progression of heart disease caused by a nuclear DNA mutation.
More DNA News and DNA Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.