Differential expression of SMAD5β in PBMC, CD34⁺, TF1, and HEL cells.

Competitor plasmids, which would yield smaller products from the same primer pair, were constructed. Serial dilutions of either the SMAD5 or SMAD5β competitor were coamplified with cDNAs from PBMCs and CD34⁺, TF1, and HEL cells. The positions of primers P1, P2, P3, and P3′ are indicated in Figure 2B. The 250-bp and 427-bp bands correspond to the native SMAD5 andSMAD5β, respectively, and the 196-bp and 373-bp bands correspond to the competitor templates. PCR products were resolved in 2% agarose gel and stained with ethidium bromide. The photographs were reversed to give a negative version.