Stem cells
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The stem cell leukemia (SCL or tal-1) gene was initially identified as a translocation partner in a leukemia that possessed both lymphoid and myeloid differentiation potential. Mice that lacked SCL expression showed a complete block in hematopoiesis; thus, SCL was associated with hematopoietic stem cell (HSC) function. More recent studies show a role for SCL in murine erythroid differentiation. ⋯ SCL expression was undetectable in immature cells of nonerythroid lineages, including pro-B cells, early thymic progenitors, and myeloid precursors expressing the M-CSF receptor. SCL expression was also absent from all mature cells of the nonerythroid lineages. Although low levels of SCL were detected in lymphoid- and myeloid-restricted progenitors, our studies show that abundant SCL expression is normally tightly linked with erythroid differentiation potential.