IQ1 decreases the size of the lung and dramatically decreased the number of branching tips. Despite the branching inhibition at the distal tips, IQ1 causes an elongation of the proximal airway compared to the control lung at E14.5. This elongation of the proximal airways suggests that the impact of IQ1 is not due simply to growth inhibition. IQ1 also inhibits branching with 3 day treatment initiating at E9.9; IQ1 causes airway dilation and decreased the density of mesenchymal cells. IQ1 also affects cardiac and vascular system development. IQ1 decreases the expression of distal genes and increased the expression of proximal genes in the lung explants consistent with the hypothesis that inhibition of the β-catenin/p300 interaction proximalizes lung epithelium.
