A transcription factor Nkx2-1 (also known as TTF-1) regulates the expression of different sets of genes. Gene expression analysis was performed using mRNAs from Nkx2-1-induced A549 cells compared to that from the control A549 cells. We used microarrays to detail the global program of gene expression controlled by Nkx2-1 and identified distinct classes of up-regulated and down-regulated genes. Overall design: mRNAs were isolated from control and Nkx2-1-induced A549 cells and hybridized on Affymetrix microarrays. We sought to identify genes influenced by Nkx2-1.