Fig. 4. p24 expression in Xenopus tissues. (A) Nothern blot analysis of Xenopus p24₃, -ß₁, and -₃ mRNAs. Equal amounts of RNA were loaded and Xenopus GAPDH was used as a control for RNA loading and integrity. The positions of the 18S and 28S Xenopus ribosomal RNAs are indicated. (B) Western blot analysis of the Xenopus p24 proteins using antibodies against lumenal epitopes of the respective p24 proteins.