Kimura applied this method to perform lineage tracing by letting the embryos grow and watching what happens. “Using transgenic animals with photo-conversion is a very new twist we devised in the lab to figure out the fates of embryonic cells,” said Srivastava. You can then zap the cells with a laser to turn individual green cells of the embryo into a red color. Kaede is photo-convertible, which means shining a laser beam with a very specific wavelength on the green will convert it to a red color. Ricci used transgenesis to create a line that caused embryo cells to glow in fluorescent green due to the introduction of the protein Kaede into the cell. The researchers knew that worm hatchlings contain aPSCs, so reasoned they must be made during embryogenesis. Images showing how single cells of the embryo were specifically and systematically converted to red color (Credit: Julian Kimura) “They’ve mostly been studied in the context of adult animals,” said Srivastava, “and in some species we know a little bit about how they might be working, but we don’t know how they are made.” But in no species so far has anyone been able to figure out how these stem cells are made in the first place. There are some unifying features of these stem cell populations in adult animals such as the expression of a gene called Piwi. miamia make these stem cells, I felt we could better understand what gives certain animals regenerative abilities.” “These cells are responsible for re-making missing body parts when the animal is injured. “One common characteristic among animals that can regenerate is the presence of pluripotent stem cells in the adult body,” said Kimura. Kimura (PhD ’22) to pursue his question of how these stem cells are made. This method allowed lead author Julian O. miamia. Transgenesis is a process that introduces something into the genome of an organism that is not normally part of that genome. miamia began to produce many embryos that could easily be studied.Ī previous study by Srivastava and co-author postdoctoral researcher Lorenzo Ricci developed a protocol for transgenesis in H. miamia in the field many years ago because of its regenerative ability. Senior author Professor Mansi Srivastava collected H. miamia into pieces and each piece will grow a new body including everything from a mouth to the brain. miamia, also known as the three-banded panther worm, is a species that can fully regenerate using aPSCs called “neoblasts.” Chop H. In a new study in Cell researchers in the Department of Organismic and Evolutionary Biology at Harvard University have identified the cellular mechanism and molecular trajectory for the formation of aPSCs in the acoel worm, Hofstenia miamia. But, many distantly-related invertebrates have stem cell populations that are pluripotent in adult animals, which means they can regenerate virtually any missing cell type, a process called whole-body regeneration.Įven though these adult pluripotent stem cells (aPSCs) are found in many different types of animals (such as sponges, hydras, planarian flatworms, acoel worms, and some sea squirts) the mechanism of how they are made is not known in any species. Intestine stem cells will only make intestines. In most animals and humans these cells are limited to regenerating only the cell type they are assigned to. They can repair, restore, replace, and regenerate cells.

Adult pluripotent stem cells