Fig. 2.

UV cross-linking identifies SERT distal polyadenylation element binding proteins in cytosolic extracts. (A and B) Biotinylated oligoribonucleotide probes (1 nM) were incubated with cytosolic extracts from: C6 rat astroglioma cells (C6), HEK, mouse frontal cortex (FC), mouse midbrain tissue (MB), and primary mouse astrocyte culture (astrocyte). Probes were covalently cross-linked to bound proteins by exposure to UV light (254 nm). Specific binding was assessed by comparing reactions with probe only (−) to reactions with 100-fold excess (100 nm) unlabeled probe (+). (A) SERT1 probe. Prominent specific bands of ∼60 kDa and 76 kDa (gray arrows) were present in C6 and HEK extracts. Less consistent cross-linking of similar bands was detected in FC, midbrain, and primary astrocyte extracts. (B) SERT2 probe. Consistent specific cross-linking to bands of ∼60 kDa and 76 kDa was observed in all extracts.