General Flashcards
What is a stem cell?
A cell that can differentiate into other cell types and can self-renew long-term.
What is a multipotent stem cell?
A multipotent stem cell can differentiate in a limited range of cell types (e.g. one tissue).
What is a pluripotent stem cell?
A pluripotent stem cell can differentiate into cells from all three germ layers.
What is a totipotent stem cell?
A totipotent stem cell can differentiate into all cell types in the body, including the extraembryonic cells. ESCs are totipotent during the first few divisions.
What is an adult stem cell?
A multipotent stem cell that has been generated from adult tissue. Clinical application possible.
What is an embryonic stem cell?
A pluripotent stem cell that has been generated from an embryo. No current clinical application.
How do you demonstrate that a cell is a stem cell?
Showing the multipotency, the potential to self-renew long-term, and the presence of specific SC markers. Used methods include the colony forming assay, the (serial) transplantation assay, lineage tracing, flow cytometry.
How many base pairs are there in the human genome?
3 billion base pairs
The KO of a gene might cause the death of the embryo. How would you knock out the gene of interest preventing this? Explain 2 methods.
The knockout of the gene can be inducible, e.g. with the Cre-ERT2 system which only activates by administration of tamoxifen. The other method can be conditional knock out using tissue-specific promotors.
Models to study human stem cells.
iPSCs, organoids, and xenotransplantation models.
What are challenges when visualizing cytokines of the niches with immunostaining and what method can be used to solve this?
Cytokines are secreted from the cell, which leads to a low antigen density. Immunostaining has low sensitivity so these weak signals can often not be detected. The proximity ligation assay (PLA) can be used to solve this. PLA can amplify single antibody binding events by rolling circle amplification, which can be visualized using a microscope.
