RT-PCR analysis of RNA expression from the CD45 transgene.

The RT-PCR products were amplified from RNA isolated from splenocytes and thymocytes and visualized by Southern analysis. Cells were isolated from C57BL/6 (C57), transgenic F (F), or CD45-null (K) mice. RNA from the SJL pre–B-cell line, SJL.1, was used as a positive control. Spleen cells were untreated (Spleen), exposed for 3 days to ConA, or treated with LPS for 3 days. Thymocytes were untreated (Thymus). The amplification primer sequences are located in exon 2 and exon 9, flanking the region of alternative exon splicing. The oligonucleotide probe also is located in exon 2, downstream of the amplification primer. The exons present in each fragment are indicated.