FIGURE 5.

Internal deletion of the −1.57- to −1.38-kb segment diminished the low substrate stiffness-induced repression of mouse Cnn2 promoter. A, CAT-ELISA data from promoter analysis in transiently transfected HEK293 cells cultured on plastic dishes showed that the −1.57- to −1.38-kb internal deletion did not affect the high level transcription in cells on high stiffness substrate. The expression level of the internal deletion construct was similar to that of the −2.12- −1.57-, and −1.38-kb 5′ truncation constructs and significantly higher than the levels of the −1.24- and −1.00-kb truncation constructs. B, stable transfection experiments showed that deletion of the −1.57- to −1.38-kb segment in the −2.12-kb promoter construct abolished the soft substrate-induced suppression of transcription as compared with that seen with the −2.12- and −1.57-kb constructs. This loss of regulation is similar to that in the −1.38- and −1.24-kb truncation constructs. ***, p < 0.001 versus the −2.12-, −1.57-, −1.38-, and 1.57- to −1.38-kb internal deletion groups. ###, p < 0.001 versus the −2.12- and −1.57-kb groups. The results were summarized from experiments using three or more original stable transfected clones in each group.