Measurement of gene expression
Total RNA was extracted from the entire small intestine as previously described [21]. Quantitative, real-time RT-PCR was used to measure expression of specific genes using the previously described primers [21]. Values were normalized to GAPDH mRNA and expression of this housekeeping gene is not altered in the CF mouse small intestine [21]. Expression of the major intestinal mucin, Muc2, was also measured using the forward (5'-GAC TTC GAT GGA CAC TGC TC-3') and reverse (5'-CAC GGT GTT TAT CTA CCA AC-3') primers.