Schematic depiction of the effects of RAR agonists and antagonists on cultured hematopoietic progenitor cells.

The effects of all-trans retinoic acid (ATRA) on various hematopoietic progenitor cell compartments during culture of lin− c-kit+ Sca-1+ hematopoietic precursors for 7 and 14 days with 1 μmol RAR agonist, ATRA, or 1 μmol RAR antagonist, AGN 193109, compared with the magnitude of the progenitor compartments of the noncultured hematopoietic precursors are shown. The magnitude of the effect is indicated by the number of arrows, with 1 arrow representing the smallest effect and 4 arrows representing the largest effect. Arrows indicate as follows: ↔, maintenance in potential; ↑, increase in potential; ↓, decrease in potential. *denotes effects seen only at 7 days of culture. Abbreviations: LTRC, long-term repopulating stem cell; STRC, short-term repopulating stem cell; pre–CFU-S, pre–colony-forming unit-spleen; CFU-S, colony-forming unit-spleen; D8, day 8; D12, day 12; CFC, colony-forming cell.