Figure 4. RT primed by endogenous random primers (ERP). (A) UnDNased RNA sample from HeLa cells was used in RT without adding primers. The RT product (1/20) was used as the template in PCR with the F70+R1067 for CCND1, F136+R822 for CDK4 and F123+R683 for HPRT1, respectively. As a negative control, the same CDK4 primers were used in a PCR with H₂O to replace the RT product as the template (lanes 1 vs. 3). (B) RNA samples from Hela, PC-3 and ZR75-1 cell lines were treated with DNase I, followed by inactivation of the enzyme. RT was then performed without adding primers. The RT product was used as the template in PCR amplification of CCND1, CDK4 and HPRT1 as in (A) or of c-myc with the F125+R838 primers. In an addition, CCND1 PCR, the RT product, was superseded by H₂O as the template.