megakaryocyteerythroid

Megakaryocyte-erythroid (ME) lineage refers to a bipotent hematopoietic progenitor population that gives rise to both megakaryocytes, which produce platelets, and erythrocytes, which are red blood cells. In adult bone marrow, ME progenitors originate from hematopoietic stem cells through the common myeloid progenitor stage and are identified as megakaryocyte-erythroid progenitors (MEPs). The bifurcation into megakaryopoiesis and erythropoiesis is regulated by extracellular signals, notably thrombopoietin (TPO) promoting megakaryocytic differentiation and erythropoietin (EPO) promoting erythroid development, with modulating contributions from cytokines and iron availability.

The differentiation programs are governed by a network of transcription factors. GATA-1 is essential for both lineages; its activity, together with cofactor FOG-1, supports erythroid maturation and megakaryocyte development. TAL1/SCL is a key driver of megakaryopoiesis, while KLF1 (EKLF) promotes erythroid maturation. FLI1 favors megakaryocyte fate. The balance of these factors, together with chromatin state and signaling cues, determines lineage choice.

Functionally, erythroid differentiation yields red blood cells capable of oxygen transport, whereas megakaryocytes shed platelets that participate in hemostasis. In fetal development, the ME lineage contributes to embryonic hematopoiesis in the fetal liver; in adults, it resides in bone marrow.

Clinical relevance includes exploration of ME progenitors in hematologic disorders and their potential as targets in therapies aiming to modulate red cell or platelet production. The concept of ME progenitors underscores a tightly regulated decision point within myeloid development.