Fig 4.

Overexpression of activated Notch1 up-regulates the let-7a microRNA expression in human epithelial cell lines. A. The indicated cell lines were retrovirally transduced with intracellular domain of Notch1 (Notch1 ICN) or control vector and total RNA isolated from subconfluent cell monolayers followed by Northern analyses of the let-7a mature microRNA expression. The autoradiograms were scanned and the intensity of bands quantified using the LabWork^™ imaging analysis software (UVP). The relative let-7a expression in ICN-over-expressing cells relative to their vector controls are shown below the lanes. A comparable RNA loading between control and ICN lanes is shown by U6. The results are representative of two independent experiments. B. Western blot analysis of Notch1 ICN and β-actin (loading control) proteins in aliquots of the cell samples used for Northern blotting in A.