DNA replication occurs more slowly in totipotent stem cells

Totipotent stem cells appear to have a slower rate of DNA replication than other cell types, which may be linked to their efficiency at differentiating.

Totipotent stem cells are present in very early-stage embryos and have the ability to differentiate into any type of cell in an organism. As such, they have great potential to inform developments in regenerative medicine, but in many ways, they are still poorly understood.

'We found that in totipotent cells, DNA replication occurs at a different pace compared to other more differentiated cells. It is much slower than in any other cell type we studied,' said Dr Tsunetoshi Nakatani from Helmholtz Munich and Ludwig-Maximilians-Universität München, Germany, first-author of the study published in Nature.

DNA replication is the important process during which a cell copies its entire genome before it divides, so that both the original and new cell will have the same genetic information. After discovering that the speed of DNA replication is slower in totipotent cells, the research team wanted to test whether they could replicate this in the laboratory. They achieved this by slowing down DNA replication by limiting the substrate that the cells use to synthesise DNA and observed that it increased the efficiency of cell reprogramming.

'Nature has made them [totipotent cells] so incredibly capable of generating all cell types of our bodies... this new concept is very simple, yet extremely important and we believe that it is a huge advance for stem cell therapy' explained study leader Professor Maria-Elena Torres-Padilla.

Totipotent stem cells may undergo this process more slowly than other cells to reduce errors. The team says that this finding may help to improve the effectiveness of regenerative medicine, although note that there is still much to learn before stem cell therapies can become optimised.