Figure 1.

Sequence alignment of human (Upper) and mouse (Lower) exon 1B (in uppercase) and promoter B (in lowercase). Numbering corresponds to the inserts of pBSX2.0 and pBSX8.0, respectively. The human PvuII site (see Fig. 6) is indicated. The open triangle indicates the position at which the luciferase coding sequence was inserted to make pGL3/UtroB/F. The deduced translation of exon 1B is shown; amino acids marked in boldface type are identical between the human and mouse sequences. The conserved splice donor consensus is shown in gray. A putative Ap1 site and an initiator-like element (Inr) are 100% conserved and indicated in black. A solid arrow marks the single transcription start indicated by primer extension; numbers adjacent to the sequence indicate the number of individual 5′ RACE clones that terminated at the positions shown.