DNA sequence of the upstream elements of the mouse c-fms gene encompassing exon 1.

Panel A shows 1 kb of the 5′ upstream sequence before the translational start site “ATG” (boxed) within exon 2. The arrow at “−72” indicates the beginning of exon 2. The arrowheads indicate the 3′ boundaries of exon 1. Boldfaced letters specify the splicing donor and acceptor sites. The sequence of exon 1 probe used for analysis in Figure 2 is underlined. (B) The splicing variants of exon 1. The number of arrowheads at each location represents the number of appearances of different exon 1 start sites from the sum of both the 5′RACE and e14 placental library screening experiments. GA and GT are splicing donor sites while AG and CAG are splice acceptors. The arrow shows the beginning of exon 2.