Semiquantative PCR analysis of levels of Hek8, Hek11, and β-actin expression in purified lymphoid cell subpopulations. Positive controls consisted of PCR reactions on cDNA from fetal brain and the Bjab cell line, both containing high levels of Hek11 transcripts (see figs 7 and 8). Negative controls contained all components of the PCR reaction except for the target cDNA (water control). At the indicated cycle number, 5-μL aliquots were removed from the PCR reaction mixture, separated on an agarose gel, and processed for hybridization with the Hek8, Hek11, or actin probe.