Detection of retrovirally transduced EpoR sequences in spleens from infected animals. (A) Plasmid DNA (lanes 1–4) or splenic RNA (lanes 5–9) were amplified by PCR or RT-PCR with a sense primer from the Stat3 site containing Y343 and an antisense primer from the SFFV vector. The lanes correspond to plasmids pSFF-R129C (lane 1) pSFF-R129C/343-S3 (lane 2), pSFF-R129C/401-S3 (lane 3), pSFF-R129C/343/401-S3 (lane 4), splenic RNA from an uninfected mouse (lane 5) or mice infected with SFF-R129C/343-S3 (lane 6), pSFF-R129C/401-S3 (lane 7), or pSFF-R129C/343/401-S3 (lanes 8 and 9). (B) A similar analysis was performed with a sense primer from the Stat3 site containing Y401 and the antisense primer from the SFFV vector. Results from the analysis of splenic RNA samples are shown in lanes 1–5, in the order indicated in A. Results from plasmid DNA analysis are shown in lanes 6–9, in the order indicated in A.