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. 2018 Jul 24;2(2):161–173.

Figure 5.

Figure 5

Footprint of SBF on the U4X enhancer region. A restriction fragment encompassing the U4X enhancer region was labeled on either the upper or lower strand at approximately position −105, incubated with affinity-purified SBF, and partially digested with DNase I. The sample was loaded on a preparative EMSA gell and bands corresponding to bound (B) and unbound (U) DNA fragments were eluted and run in separate lanes of a sequencing gel. The lanes labeled C + T contained chemical sequencing reactions as markers. The region protected from DNase I digestion by bound SBF is indicated by brackets alongside the autoradiograms. The protected region is also denoted at the bottom of the figure by horizontal lines above and below the DNA sequence of the U4X enhancer region. Dots indicate sites of enhanced DNase I cleavage induced by the binding of SBF. The rectangular box labeled SPH points out the 18 bp of sequence similarity shared with the U4B and Ul SPH motifs. The nearby octamer sequence variant is shown in bold type.