Expression profile of the Gr B gene and the other Grs of the murine Gr B locus in +/+ and mi/mi CMCs. (A) Serially diluted total RNA (0.5, 0.05, and 0.005 μg) from +/+ andmi/mi CMCs, and splenocytes of +/+ mice were reverse-transcribed and PCR-amplified with the Gr B–specific (uppermost panel) or Gr C-G–specific (lower two panels) primers. The PCR was stopped after the indicated number of cycles, loaded on 2% agarose gels, and stained with ethidium bromide. As a positive control, +/+ splenocytes were used after PWM-stimulation. Molecular size standards are shown on the right. (B) Five micrograms of total RNA from +/+ and mi/mi CMCs, and +/+ splenocytes stimulated with PWM were fractionated on 1% agarose gels and fixed onto nylon membranes. The PCR-amplified DNA fragment seen in (A) was used as a probe to detect the Gr B–specific (upper panel) and the Gr C-G–specific (lower panel) transcripts. Reprobing with the β-actin probe showed that equal loading had been achieved.