THE SCL PROTEIN DISPLAYS CELL-SPECIFIC HETEROGENEITY IN SIZE

Abstract

SCL protein production was examined in a variety of hemopoietic cell lines by immunoblotting using specific polyclonal antisera. SCL protein was detected in erythroid, megakaryocyte, mast and early myeloid cell lines, as well as in several lymphoid leukemia cell lines which are known to harbor SCL gene rearrangements. In most cell lines, proteins of molecular weight 49 and 44 kDa were found, however two myeloid cell lines expressed only lower molecular weight species of 24 and 22 kDa. This size discrepancy appeared to be due to cell-specific translational regulation, since overexpression of a retrovirally transfected SCL gene yielded the higher molecular weight forms in most cell lines (GP+E..