A1, A BCL-2 FAMILY MEMBER, PROLONGS CELL-SURVIVAL AND PERMITS MYELOIDDIFFERENTIATION

A1, a bcl-2 family member, has been identified as a hematopoietic-spec ific, early inducible gene, In this study it is shown that stable tran sfection of A1 into an interleukin-3 (IL-3)-dependent myeloid precurso r cell line, 32D cI3, leads to a retardation of IL-3 withdrawal-induce d cell death similar to that observed with transfection of bcl-2. Howe ver, unlike bcl-2 A1 expression permits the accumulation of differenti ated myeloid cells both before and after IL-3 withdrawal. Total cell a ccumulation, on the other hand, is considerably greater after IL-3 dep rivation in the bcl-2 transfectant than in Al-expressing cells. Cells cotransfected with the two genes behave similarly to cells singly tran sfected with bcl-2, except that viability following IL-3 withdrawal is somewhat further enhanced. These results suggest that these two prote ins have distinct roles that may be related to the divergent regulatio n of their expression during myeloid differentiation. (C) 1996 by The American Society of Hematology.