Primary but not secondary granule genes are expressed in PU.1-deficient neutrophils. RNA was prepared, reverse transcribed, and subjected to PCR as described in Materials and Methods. Data shown are from representative normal (+/+) and PU.1-deficient (−/−) cells cultured for 2 weeks as described in Materials and Methods. Controls for amplification of DNA in the absence of reverse transcription for each reaction were negative; these data are not shown. β act, β actin; NE, neutrophil elastase; MPO, myeloperoxidase; LF, lactoferrin; NG, neutrophil gelatinase; LZ, lysozyme.