Sequence complexity of polyadenylated RNA from seizure-susceptible El mouse brain polysomes.

The hybridization kinetics in the complementary DNAs (cDNA) to polyadenylated messenger RNA (mRNA) in the brain of seizure-susceptible El mice were examined to elucidate the correlation between seizure susceptibility and genetic expression. Homologous and heterologous saturation hybridizations indicated that cDNA of seizure-nonsusceptible ddY mice hybridized with less mRNA in seizure-experienced El(+) or seizure-nonexperienced El(o) mice than that in ddY mice, cDNA of El(+) mice hybridized to a lesser extent with mRNA of El(o) mice than that of ddY or El(+) mice, and no difference was observed with cDNA hybridization results of El(o) mice to individual mRNAs of ddY, El(+) or El(o) mice. The results suggest that some sequences found in mRNA of ddY are lacking in both El strains and are responsible for the inbred predisposition, while those present in El(+) mRNA but missing in El(o) may associate with seizure susceptibility, since common sequences are present in the mRNA of those groups of animal. The sequence diversity among the 3 groups of mice was mainly observed with the rare class of mRNA. Molecular cloning of the cDNA corresponding to this class of mRNA found in the El(+) mice would clarify the gene expression in the brains of epileptics.