ACTA1 and Renal cyst: We found that the mRNA levels of transforming growth factor β (TGF-β), α-SMA, Col I and Col III were increased in cystic kidneys from PN21 and PN28 Pkd1flox/flox:Pkhd1-Cre mice versus those in kidneys from age matched wild type mice as examined by qRT-PCR analysis (Supplemental Figure S2).