FLOW CYTOMETRIC MEASUREMENT OF RNA-SYNTHESIS BASED ON BROMOURIDINE LABELING AND COMBINED WITH MEASUREMENT OF DNA CONTENT OR CELL-SURFACE ANTIGEN

RNA synthesis can be analysed in nuclei or cells labelled with 5-bromo uridine (BrUrd) and stained using cross-reacting anti-bromodeoxyuridin e (BrdUrd) antibody. Flow cytometric dual parameter analysis of BrUrd incorporation and DNA content in nuclear suspensions of human blood ly mphocytes showed that RNA synthesis increased within the first 24 hour s of phytohemagglutinin (PHA) stimulation, reaching a maximum at 48 ho urs, when cells had entered the cell cycle. Using a new method for flo w cytometric dual parameter analysis of BrUrd incorporation and a cell surface antigen, spontaneous RNA synthesis in HL-60 and K-562 cells w as measured simultaneous with CD13 expression.