SpaceA maps distant DNA contacts while keeping tissue locations
SpaceA
A method that maps distant DNA contacts while preserving tissue locations.
chromatin
DNA packed together with proteins inside a cell nucleus.
A/B compartments
Two labels used to describe different parts of folded DNA.
What happened
A team led by Professor Li Xiang at the Chinese Academy of Sciences developed SpaceA. It maps distant contacts between DNA regions inside tissue sections. It also keeps the locations of cells within those tissues. DNA is packaged with proteins into chromatin. Chromatin folds into a complex three-dimensional shape inside the nucleus.
How the method works
SpaceA combines two approaches. The first uses microfluidic spatial barcoding. Tiny fluid channels give molecular labels to different tissue locations. This tells researchers where an interaction happened. The second approach detects chromatin contacts without physically joining DNA fragments. Together, the two steps show both contact and location.
Earlier single-cell 3D genomics methods improved views of genome structure. However, they usually lost the original positions of cells inside tissues. Other spatial methods used ligation-based Hi-C strategies. Those methods mainly detected shorter-range contacts, often within 10 megabases. SpaceA was designed to examine longer-range contacts as well.
What the researchers saw
The team tested SpaceA on nine mouse embryo tissue sections. The sections covered four developmental stages, from embryonic day 11.5 to day 14.5. The experiment produced about four terabytes of deeply sequenced data.
A/B compartments changed dramatically between embryonic days 12.5 and 13.5. This shift happened alongside major changes in transcript information. The researchers also found a special pattern in the embryonic liver. It did not follow the usual A/B compartment model.
In the liver, mid-range contacts from 10 to 40 megabases became stronger. Contacts between neighboring compartments also strengthened. Long-range contacts between different chromosomes, above 40 megabases, became weaker. Microscopy showed heterochromatin adhesion inside liver cell nuclei. The pattern came with a broad decline in gene expression.
These findings describe changes observed in the same samples. They do not prove that one DNA contact caused the gene-expression decline.
Why it matters
DNA structure is studied to understand how cells organize their genetic material. Tissue location adds an important layer of information. Cells in one tissue can sit in different environments. A method that preserves location can connect genome architecture with tissue development.
SpaceA may therefore help researchers compare DNA folding across cells and stages. It also shows that different tissues may organize chromatin in different ways. This could improve basic studies of development. It is not yet a medical tool.
What is confirmed
The published study showed that SpaceA could collect spatial 3D genome data from nine mouse embryo sections. It captured changes across several developmental stages. It also revealed a liver pattern that differed from the usual compartment model.
What remains unknown
The study did not show whether human tissues use the same pattern. It also did not establish whether the contacts directly control specific genes. Researchers still need to test other tissues, ages, and biological conditions. They must also determine how widely the liver pattern applies.
What to watch next
Future work will likely examine more developmental stages and tissue types. Researchers can then connect particular DNA contacts with particular gene changes. They can also test whether the patterns repeat in other species. The main question is whether SpaceA becomes a reliable bridge between DNA structure and tissue biology.
Sources: Phys.org report, Developmental Cell paper.
A new way to see DNA folding inside tissues
📰 Full story: SpaceA maps distant DNA contacts while keeping tissue locations
Scientists built a method that sees DNA folding and cell location together. It revealed a different pattern in mouse embryo liver cells.
SpaceA
A method that studies DNA folding while keeping cell locations.
chromatin
DNA and proteins packed together.
A/B compartments
Two sections used to describe DNA folding.
💡 The gist
- DNA is very long, so cells fold it inside the nucleus.
- SpaceA sees the folding while keeping each cell's location.
- Mouse embryo liver cells showed a special folding pattern.
The Chinese Academy of Sciences, a research organization, led this work. Professor Li Xiang led the research team. They developed SpaceA, a method for studying DNA structure in tissue.
DNA joins proteins to form chromatin. Chromatin folds into a three-dimensional shape. Researchers want to know which DNA regions interact. They also want to know where those interactions happen.
Older methods had important limits. Single-cell methods could show 3D DNA structure. However, they often lost each cell's place inside the tissue. Some spatial methods kept locations. Yet they mainly saw nearby DNA contacts.
SpaceA combines two techniques. Tiny fluid channels label different tissue locations. Another technique finds contacts without joining DNA pieces. This helps researchers connect a contact with its place.
The team studied nine mouse embryo tissue sections. The sections covered four stages. They ranged from embryonic day 11.5 to day 14.5. A/B compartments changed greatly between days 12.5 and 13.5. Gene activity information changed during the same period.
The liver showed a different pattern. Some medium-distance contacts became stronger. Contacts between neighboring compartments also strengthened. Very distant contacts between chromosomes became weaker. These findings show that DNA folding can change in different ways.
The results are observations, not proof of cause. The study does not show that humans use the same pattern. It also does not show which contact changes control each gene.
Researchers will study more tissues and stages. They will connect specific contacts with specific gene changes. This may explain how tissue cells develop. It is still basic research, not a medical treatment.
A new way to see DNA folding
📰 Full story: SpaceA maps distant DNA contacts while keeping tissue locations
Scientists found a way to look at folded instructions inside cells.
DNA
Tiny instructions that help a body grow.
SpaceA
A way to see how DNA folds.
embryo
A baby animal growing before birth.
Your body has tiny cells. Each cell has DNA. DNA is like a very long instruction sheet. It folds to fit inside the cell.
Scientists made SpaceA. SpaceA is a way to see DNA's folds. It also records where each cell was.
They looked at mouse embryo tissue. In liver cells, the folding pattern was different. Some far parts appeared together more often. Other very far links appeared less often.
We do not know if human cells match. More studies will look at other cells.