Down-Regulation of GATA-2 Transcription during Pneumocystis carinii Infection

Differences in gene expression between Pneumocystis carinii-infected and noninfected rats were examined. Total RNA was isolated from homogenized rat lungs and then subjected to differential display with combinations of oligo(dT) and various arbitrary PCR primers. Approximately 50 differentially expressed bands were observed. Several of these DNA bands were isolated, reamplified, and cloned. The cloned DNA fragments were used as probes to perform Northern hybridization on RNA from P. carinii-infected and noninfected rat lungs. One clone was found to react with a 3-kb mRNA from noninfected but not from P. carinii-infected rat lung, suggesting that the gene represented by this clone was down-regulated during P. carinii infection. The nucleotide sequence of this clone was determined and found to be 97% homologous to the mouse GATA-2 transcription factor. In situ hybridization using RNA probes derived from this clone revealed that alveolar macrophages, resident lung monocytes, and bronchial epithelial cells express the GATA-2 gene in the lung.