Figure 2.

Expression of the UH genes. A. 5 μg RNA from duplicate samples of CHO cells transfected with the U₅H, U₅₀H or H2a-614 genes were analyzed by SI nuclease mapping using the H2a-614 gene labeled at the 3′ end of the Aval site at codon 20 as a probe. The protected fragments are: H2a_H–protection of the endogenous hamster H2a mRNAs. H2a_M–protection of the RNA expressed from the transfected genes. Band P is the probe band. The RNA samples are indicated under each lane. In the lanes labeled CHO, RNAs from untransfected CHO cells were analyzed. The marker (last lane on the right) is pUC18 digested with HpaII. B. The same RNA samples as in A were analyzed by S1 nuclease mapping using either the U₅₀H gene (lanes 1–4), or the U₅H gene (lanes 5–8) labeled at the 5′ end of the Aval site as a probe. Lanes 1, 2, and 7 are analyses of RNAs from cells transfected with the U50H gene, Lanes 3, 5, 6 are analyses of RNAs from cells transfected with the U5H gene. Lanes 4 and 8 are analyses of RNAs from cells transfected with the H2a-614 gene. Lanes 2 and 7 and lanes 3 and 6 contain the same RNA samples. The protected fragments are: H2an-protection of the endogenous hamster H2a mRNAs; H2aM - protection of the mouse H2a-614 mRNA; U1₅–protection of the RNA from the U₅H gene starting at the U1 RNA start site; U1₁₅–protection of RNA from the U1₅₀H gene starting at the U1 start site. P indicates the undigested probe fragment. In lanes 3 and 7, the RNAs are mapped to the point of divergence between the U1₅H and U1₅₀H genes. Lane M is marker pUC18 digested with HpaII.