Use of avidin-biotin subtractive hybridization to characterize mRNA common to neurons destroyed by the selective neurotoxicant trimethyltin

Trimethyltin (TMT), a selective neurotoxicant, destroys a distinct subpopulation of neurons which possess no known biochemical or anatomic linkage. However, TMT-sensitive neurons may share common gene products related to susceptibility. In an effort to isolate mRNAs common to TMT-sensitive neurons, avidin/biotin based-subtractive hybridization was used to generate a cDNA library specifically related to TMT-toxicity. Out of 50 cDNAs, two clones hybridized only to poly(A⁺) mRNA isolated from the brains of saline-treated rats. Two of these cDNAs, p9T10 and p9T19, were used for in situ hybridization; both hybridized to hippocampus, limbic cortex, amygdala and other regions destroyed by TMT, suggesting that these probes identified mRNA enriched in TMT-sensitive neurons. The patterns of in situ hybridization coupled with the loss of p9T10 and p9T19 hybridization to mRNA isolated from the brains of TMT-treated rats suggests that one or both of these two clones may represent mRNA found in neurons damaged by TMT. The combination of selective neurotoxic lesions followed by cDNA subtractive hybridization should prove to be a useful strategy for the isolation of gene products from specific neuronal populations.