FIG. 1.

Generation of Eμ-pp-E2F1 transgenic mice. (A) Transgene expression vector contains a duplicate version of the immunoglobulin heavy-chain enhancer (Eμ) inserted in the mouse pim1 promoter region (pp), followed by the Moloney murine leukemia virus long terminal repeat (LTR), which provides transcription termination sequences. The 3′ end of the human HA-E2F1 cDNA is fused to the SV40 small t antigen intervening sequence (IVS) of the pJ3Ω vector and provides an extra splice donor (SD) and splice acceptor (SA) site. (B) Immunoblotting shows E2F1 expression levels in total cell extracts from different tissues of 4-day-old Eμ-pp-E2F1 transgenic mice of two independent founder lines (TEF1-5 and TEF1-43) compared to control littermates. Actin serves as a loading control. Thym, thymus.