Figure 2 of Song, Mol Vis 2008; 14:161-170.

Figure 2. Detection of p16INK4a, p21WAF1/CIP1, p27KIP1, and p53 mRNA. Electrophoretic gels show the presence of mRNA for the four senescence-related genes. Lane 1 to Lane 5 shows HCECs of the 20-, 30-, 40-, 50-, and 60-year-old groups, respectively. Lane 6 is the negative control. Lane M is Marker DL 2000. All bands migrate to their expected product length as summarized in Table 1.