1. to flattened type I-like cells until by type II cells from TGF-a knockout mice
2. weeks 100% of the cells appear differen- were cultured in serum-free medium and
3. tiated. Monolayers formed by mouse type monitored over 4 weeks. Cells from knock
4. II
cells exhibit transepithelial resistances out mice attach more rapidly are 55%
5. that are approximately 50% higher than larger and are proportionately less numer