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Fig. 6. Gel shift analysis of the (GTTT)4 sequence. (A) Incubation of an
32P-labeled oligo containing the (GTTT)4 sequence with
Drosophila embryonic extracts causes the formation of several
complexes (arrows). Most of these complexes can be competed by excess cold
probe (lane 2), but not by the mutant probe (lane 3). Complexes are not formed
with the mutant probe (lane 4). (B) Slp1 protein binds specifically to the
(GTTT)4 repeat. Increasing concentrations of a bacterial extract
containing full-length Slp1 protein (lanes 4-6) causes formation of a specific
complex (arrow). Binding can be competed by excess cold probe (lane 7), but
not by the mutant probe (lane 8).