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Figure S2. Ribonuclease protection assays showed a direct correlation between protein production and Igκ transcription. (A and B) The mCκ RPA probe is identical to the OOF SP2 VJκ rearrangement and spans into the mCκ region, allowing differential detection of mCκ versus SP2 fusion partner expression levels. The lengths of protected fragments are indicated. The SP2 VκJκ transcript also provided a useful internal control to normalize for RNA abundance for each sample. (C) Relative transcription levels of the 15 allelically included and 2 allelically excluded hybridomas. Values were averaged from two to three independent RPA analyses for each clone.