Fig. 8. Increased Rho GDI cardiac expression stimulated accumulation of p21 transcripts and repressed cyclin A mRNA content. RNA was isolated from E9.5 embryonic hearts of the nontransgenic (NTG) or transgenic F₁ embryos from the H2 founder. Each line represents PCR reactions performed with the same cDNA synthesized from a RNA sample pooled from ten hearts using gene-specific primers for the indicated transcripts. PCR reactions were separated by polyacrylamide gel electrophoresis and quantitated by PhosphorImage analysis. For each primer set, two or three cycle-numbers were tested to be certain that PCR product accumulates within a linear range. The level for each amplified transcript was normalized to that of GAPDH. The normalized level for each transcript in the transgenic heart sample was expressed relative that in the nontransgenic heart sample.