Altered expression levels of SEF-2 and p112 in the rat hippocampus after transient cerebral ischemia: Identification by mRNA differential display

The authors used mRNA differential display to identify genes whose expressi on levels are altered in the adult rat hippocampus 24 hours after global is chemia. At this time after challenge, the basic helix-loop-helix transcript ion factor, SEF-2, and the 26S proteasome complex subunit, p112, were ident ified as genes whose expression levels are decreased and increased, respect ively, in the hippocampus. To determine the spatial and temporal patterns o f expression change for each gene, the authors antisense in situ hybridizat ion to paired brain sections of sham-operated and global ischemia-challenge d rats at 6, 12, and 24 hours after reperfusion SEF-2 expression was not si gnificantly altered from that of sham-operated controls in any hippocampal subfield at or before 12 hours after challenge. At 24 hours after ischemia, however, SEF-2 expression levels were significantly diminished in the vuln erable CA1 subfield, but not in the less vulnerable CA3 or dentate granule cell subfields. The proteasome p112 subunit gene displayed no change in exp ression levels at 6 hours after insult; however, an elevated expression was observed at 12 hours after challenge in the dentate granule cell subfield. By 24 hours after challenge, p112 expression was significantly elevated in both the CAI and dentate granule cell subfields. These results demonstrate that a member of the basic helix-loop-helix family of transcription factor s, SEF-2, and the major subunit of the 26S proteasome complex, p112, displa y altered gene expression in the hippocampus after transient cerebral ische mia.