POLYOMA MIDDLE T-ANTIGEN IN HL-60 CELLS ACCELERATES HEMATOPOIETIC MYELOID AND MONOCYTIC CELL-DIFFERENTIATION

Expression of the polyoma virus middle T antigen in HL-60 cells accele rates their differentiation in response to both monocytic and granuloc ytic differentiation-inducing agents. Middle T-expressing cells treate d with the granulocytic inducer retinoic acid or the monocytic inducer 1,25-dihydroxy vitamin D3 differentiated 24 h earlier than parental, mock-electroporated, or vector control cell lines. The rapid onset of differentiation correlated with an increase in the cellular level of t he middle T protein as well as two known retinoic-acid-inducible marke rs in HL-60 cells: the paxillin and transglutaminase gene products. Th e accelerated functional differentiation response and expression of re tinoic-acid-inducible markers indicate that middle T played a causal r ole in differentiation. Thus, expression of the polyoma middle T antig en in HL-60 cells enhanced a variety of molecular changes associated w ith cellular differentiation. (C) 1998 Academic Press.