Expression of retinitis pigmentosa protein RP1 in human bronchial epithelial cells. Expression of retinitis pigmentosa protein RP1 in human bronchial epithelial cells. Total RNA was isolated from cultures of HBE cells on days 4, 10, and 14 of culture. RT-PCR was performed using primers specific for RP1 (top panel) or γ-actin (lower panel) with (+) or without (−) the addition of reverse transcriptase. Amplification with the RB-1-specific primers generated a clear product of the expected size, demonstrating the expression of RP1 in HBE cells. The signal appeared to increase at later time points, when more ciliated cells are present. Lawrence E. Ostrowski et al. Mol Cell Proteomics 2002;1:451-465 © 2002 The American Society for Biochemistry and Molecular Biology