Induction of the 'zinc finger' gene after transient focal ischemia in rat cerebral cortex.

An essential part of gene expression and regulation is the binding of a regulatory protein (transcription factor) to the recognition sequence of the appropriate gene. A novel protein motif for nucleic acid recognition (called 'zinc finger') is one of such transcription factors. A relationship between gene expressions of a transcription factor and heat shock protein (HSP) 70 has been suggested. Possible inductions of mRNA for 'zinc finger' and HSP70 were examined after transient focal ischemia in rat cerebral cortex by Northern blot analysis using a synthetic oligonucleotide probe for 'zinc finger' gene expression, and a human genomic DNA probe for HSP70 gene expression. After 30 min of middle cerebral artery (MCA) occlusion, the rats recovered for 1, 3, 8h, 1, 2, and 7 days (n = 5). Zinc finger gene is normally expressed in rat cerebral cortex, and is induced by transient ischemia with a maximum at 1 h after the reperfusion. In contrast, HSP70 mRNA is not expressed in normal condition, but is greatly induced by transient ischemia with a maximum at 8 h of reperfusion. These results indicate that the gene expression for a transcription factor changes in the early stage of reperfusion after cerebral ischemia before HSP70 induction begins.