THE SKI SNO PROTOONCOGENE FAMILY IN HEMATOPOIETIC DEVELOPMENT/

The ski/sno protooncogenes encode nuclear proteins that may act as tra nscription factors, We examined ski and sno mRNA expression in hemolym phopoietic lineages. The ski protooncogene is expressed in B- and T-li neage cells, mature macrophages, and mast cells. In normal murine marr ow-derived progenitors analyzed by single-cell reverse transcription-p olymerase chain reaction (RT-PCR), ski expression is limited to dual-l ineage megakaryocyte/erythrocyte colony-starts. Expression of sno is m ore limited than ski in mature cells; it is expressed in T lymphopoiet ic cells, but not in B-lineage cells. The sno protooncogene is express ed more widely than ski in myeloid progenitors, as it is found consist ently in tri-, dual-, and single-lineage progenitors, Both ski and sno are cell cycle-regulated in synchronized factor-dependent mouse myelo id cells, Expression of ski mRNA peaks in mid G(1) in cells synchroniz ed by isoleucine deprivation in the presence of growth factor, but fal ls off rapidly when growth factor is withdrawn, Expression of sno mRNA is maximal in early to mid G(1) and then oscillates as the cells cont inue through cycle, These results suggest that the ski/sno protooncoge nes play a role in hematopoiesis, growth factor responses, and cell cy cle-regulation, with the two members of the family showing differing p roperties. (C) 1995 by The American Society of Hematology.