Detection of hiNOS mRNA in Tax-expressing T-cell lines infected with HTLV-I by RT-PCR analysis. RT of cellular RNA (1 μg total RNA) and PCR were performed. One tenth of the PCR mixture was analyzed by ethidium bromide staining of 2% agarose gel. Agarose gel electrophoresis of DNA amplified by hiNOS, Tax, and β-actin primers. M: size markers. The band of specific mRNA for hiNOS is 259 bp, Tax of HTLV-I is 203 bp, and β-actin as internal control is 548 bp. The three T-cell lines, Jurkat, H9, and CCRF-CEM, are negative for HTLV-I. Other T-cell lines are positive for HTLV-I. Arrows indicate the position of the specifically amplified DNA.