Figure 2.

Individual enhancer complex proteins activate the female-specific dsx 3′ splice site. (A) Schematic representation of a dsx mini-gene RNA substrate with two synthetic MS2-hairpin enhancer elements positioned ∼300 nt downstream of the female-specific 3′ splice site. Four RS fusion proteins are expected to interact with dsx300-(MS2)₂ because MS2 binds the MS2-hairpin RNA as a dimer. (B) In vitro splicing assays were performed in the presence of saturating amounts of recombinant MS2-fusion proteins. Diagrams to the right indicate unspliced and spliced products. Average splicing rates for each MS2-fusion protein are listed below the corresponding gel. (C) The percent spliced is plotted as a function of time to determine a rate of splicing for each fusion protein tested. Filled circles indicate MS2–Tra2, open circles indicate MS2–Tra, filled diamonds indicate MS2–9G8 and filled triangles indicate MS2–2RS^(SC35/SC35).