To begin, take a vial containing the mouse bone marrow hematopoietic stem and progenitor cells. Using a micropipette, resuspend the pellet in one milliliter of ACK lysing buffer and incubate for one to two minutes at room temperature. Transfer the resuspended mixture into a 50 milliliter tube through the pre-wetted 70 micrometer cell strainer.
Then add 10 milliliters of FACS buffer to dilute the ACK lysing buffer. Centrifuge the mixture at 400 G for five minutes at four degrees Celsius and resuspend the pellet in 10 milliliters of FACS buffer by first resuspending it in one milliliter of buffer and then topping up with nine milliliters of buffer. Now, mix 10 microliters of 0.4%trypan blue with 10 microliters of the cells in a 0.5 milliliter tube, and count the cells using an automated cell counter.
To stain the cells, centrifuge the cells at 400 G for five minutes at four degrees Celsius. Resuspend the pellet in FACS buffer to achieve a final concentration of one times 10 to the seven cells per milliliter by first resuspending the pellet in one milliliter of buffer and then topping up with the remaining volume. Using a P1000 micropipette, transfer the suspension into a FACS tube through a 35 micrometer cell strainer cap.
Next, prepare staining mix as shown here. After centrifugation, resuspend the cell suspension in 300 microliters of staining mix one in a sample tube and incubate on ice for 15 minutes protected from light. Then add 300 microliters of mix two into the sample tube and incubate for 20 minutes on ice protected from light.
Add three milliliters of the FACS buffer to the single stained and mixed stained sample tubes. Now centrifuge the cell suspension. After discarding the supernatant, resuspend the pellet in 500 microliters of the FACS buffer.
Prepare a 1.5 milliliter tube prefilled with 500 microliters of collection medium. Once the FACS instrument has been calibrated, add 500 microliters of FACS buffer to the cell suspension and then transfer one milliliter of the sample through a 35 micrometer cell strainer cap into a new FACS tube. After cell sorting, transfer 10 microliters of the sorted cells into a new FACS tube containing 90 microliters of FACS buffer.
Pellet the cell suspension by centrifugation and resuspend in 50 microliters of PBS with 0.04%BSA. Transfer the suspension to a 0.2 milliliter tube and add 50 microliters of PBS with BSA to the original tube to collect any leftover cells. Transfer the cells to the 0.2 milliliter tube to reach a total volume of 100 microliters.
Run a pilot experiment to identify the best lysis time for nuclei isolation. After pelleting the nuclei, resuspend the nuclei pellet in 12 microliters of diluted nuclei buffer. Add two microliters of nuclei to a tube containing 0.4%trypan blue and eight microliters of PBS with 0.04%BSA and count the nuclei using an automated cell counter.
After completing the nuclei isolation, transfer six microliters of nuclei resuspension into a new FACS tube pre-filled with 150 microliters of FACS buffer. Add three microliters of 7-AAD and incubate for five minutes on ice.
