CONSTITUTIVELY EXPRESSED OCT-2 PREVENTS IMMUNOGLOBULIN GENE SILENCINGIN MYELOMA X T-CELL HYBRIDS

Recent experiments involving disruption of the Oct-2 gene have shown t hat this largely B cell-restricted transcription factor is not require d in the early stages of B cell development. However, B cells that lac k Oct-2 may be blocked from differentiation past the surface immunoglo bulin-positive stage. To identify a possible function for Oct-2 in the late stage immunoglobulin-secreting cell, we have used the method of somatic cell fusion. When the immunoglobulin-producing myeloma MPC11 i s fused to a T lymphoma, Oct-2 production ceases, as does the expressi on of immunoglobulin, J chain, and several other B cell-specific gene products. In the present study, we show that by preventing the loss of Oct-2 in the hybrid cells, we can preserve expression of all other te sted B cell-specific genes. These results establish a central role for Oct-2 in maintaining the genetic program of the immunoglobulin-secret ing plasmacyte.