Fig. 5. Rac1 mRNA is present in Fmr1-mRNP complexes in vivo. DNA fragments obtained from PCR were analyzed by electrophoresis in a 2% agarose gel. DNA ladders were run on both sides of the gel. Total RNA: DNA fragments derived from RT-PCR reactions with total RNA isolated from third instar larvae. Primers specific for the voltage-gated K⁺ channel molecule Hyperkinetic gave rise to DNA fragments of 0.3 kb. The band for -tubulin is 1.0 kb, and the band for Rac1 is 0.2 kb. WT: DNA fragments derived from RT-PCR reactions with RNAs isolated from the Fmr1-mRNP complexes immunoprecipitated from wild-type third instar larvae. Fmr1⁴: DNA fragments derived from RT-PCR reactions with RNAs isolated from the Fmr1-mRNP complexes immunoprecipitated from Fmr1 mutant third instar larvae.