Surprising Discovery Reveals DNA Transfer Between Human Cells

Bacterial cells are prokaryotic and basic, and carry biomolecules like proteins and DNA encased in a cellular membrane. Cells in humans and other many organisms including plants and fungi are eukaryotic, and are much more complex. They carry proteins, biomolecules and complexes, and organelles that are encased by membranes, such and a nucleus that holds the cell’s genome. Prokaryotic cells were thought to have some functions that eukaryotic cells do not, such as the ability to share pieces of DNA directly from one cell to another, in a process known as horizontal gene transfer.

So it was quite surprising for scientists to find evidence that large bits of DNA were transferred directly from one human cell to another. Not only was that DNA shared and taken up by a human cell, but it also persisted within those recipient cells and seemed to change their function in some ways. This may show that human cells have novel ways of signaling, communication, and possible even evolution that we have not recognized. The work has been reported in Cell.

The investigators determined that errors in cell division or DNA damage can generate large bits of genomic DNA that can exit the nucleus and migrate into other neighboring cells. This happens through structures called nanotubes, which are tiny little tubes that can form quickly and transiently when two cells come into contact.

The DNA may then move into the nucleus of the recipient cell and even be incorporated into its genome. DNA that was transferred from one cell to another remained in the recipient throughout multiple rounds of cell division; the transferred DNA was biologically active that entire time; and the newly acquired DNA gave the recipient cells new traits.

“This was a surprising discovery,” said study leader Peter Ly, Ph.D., an Assistant Professor in the Children’s Medical Center Research Institute at UT Southwestern (CRI), among other appointments. “Our findings suggest neighboring cells may be able to directly reshape one another’s genomes in ways we did not anticipate.”

This process was observed with live-cell microscopy while the researchers were investigating how cells react to genetic instability. The scientists saw parts of the Y chromosome moving from male to female cells, and the male genes were active and functional in the female cells. In another experiment, pieces moved from one type of cell to another, which may mean this is a general feature of cell biology in humans.

“There are many open questions. We now want to understand how widespread this process is, how it is regulated at the cellular and molecular levels, and what role it may play in human health and disease, including cancer,” Ly said. “These findings may have important implications for understanding how cancer genomes evolve and acquire large-scale chromosomal alterations.”

Sources: UT Southwestern Medical Center, Cell