Fig. 6. EMSA analysis of Eα factor binding sites. Radiolabeled probes corresponding to different Eα regions (indicated at the top of each panel) were used together with RAG^–/– (RAG) or wild-type thymocyte nuclear extracts (NE), as indicated. Unlabelled oligonucleotides used for competition analyses (A, B, D and E), as well as anti-sera used for supershift analyses (A and E), are also indicated. P.I., pre-immune rabbit serum. The position of the major complexes observed with the individual probe are indicated by arrows (C#; see details in the text). Supershifts are indicated by arrowheads. In (A), lanes 1–10 and 11–25 correspond to two separate experiments; a longer exposure is presented for lanes 11–14 to visualize the shifted bands better. The star indicates a non-specific complex that can be formed in the absence of NE. Probes and oligonucleotide competitors are defined in Table I.