Lack of eosinophil granule gene expression in a PU.1-null myeloid cell line derived from the embryonic liver of the PU.1^−/− mouse.

The cDNAs were prepared from total RNA from the bone marrow of wild-type and C/EBP^−/− mice, a PU.1-null cell line, 2 PU.1-null cell lines with restored PU.1 expression, and one with restored M-CSFR expression. Primers specific for the primary granule gene NE, the secondary granule gene B9, and the eosinophil granule genes MBP and EPX were used (35 cycles for all). Products were analyzed by electrophoresis through a 2% agarose gel and ethidium bromide staining. The 18S rRNA was amplified (15 cycles) as a control for the balance and integrity of the cDNAs.