(A) Percentage of MKs classified on the basis of nuclear lobes as evaluated by optical microscopy: cells were treated with 20 or 200 ng/mL of recombinant Tat protein starting from day 0 and harvested at day 12 (results from a representative experiment). (□) Tat 20 ng; (▪) Tat 200 ng; (▨) control. (B) Flow cytometry analysis of CD61, CD62, and CD41b expression in day 9 MKs grown in either absence (control) or presence of Tat protein (20 or 200 ng/mL starting from day 0 of culture). The negative control is shown on the far left in each panel (thin line peak).