Figure 2.
Photocross-linking to CFTR integration intermediates. CFTR mRNAs, codons 837 through the stated truncation site, containing UAG codons at the sites indicated were transcribed and translated in the presence of εANB-lys-tRNACUA as described in Materials and Methods. Puromycin (Puro) was added for 10 min where indicated, and samples were irradiated with UV light (UV) to activate the ANB moiety. Single and double asterisks indicate migration of nonglycosylated nonread-through and read-though polypeptides, respectively. Photoadducts are indicated by upward arrowheads. Diagrams show predicted location of CFTR nascent polypeptide and TM7-8 within the ribosome translocon complex. Location of εANB-Lys probe is shown by circle (aa 913). The number of residues separating the εANB-Lys probe site from the ribosome peptidyl-transferase center is indicated by d.