Increased expression of c-fos mRNA and AP-1 transcription factors after cortical impact injury in rats.
Levels of c-fos mRNA and AP-1 transcription factors co-expression were measured in a controlled lateral cortical impact model of traumatic brain injury (TBI) in rats. Ipsilateral cerebral cortex and bilateral hippocampal c-fos mRNA increases were revealed by in situ hybridization after lateral cortical impact injury. Based on regional in situ hybridization data, we employed semi-quantitative RT-PCR methods to study the temporal profile of changes in the ipsilateral cortex at the site of injury. We found that TBI produces transient increases of c-fos mRNA expression in the ipsilateral cerebral cortex at 5 min postinjury, which peaks at 1 h postinjury and subsides by 1 day postinjury. Gel shift nuclear protein binding assays showed that AP-1 transcription factor binding was robustly increased in injured cerebral cortex at 1 h, 3 h, 5 h and 1 day after injury. These data indicate that TBI can produce significant increases in c-fos expression and subsequent upregulation of the AP-1 transcription factors. Thus, AP-1 transcription factors modulation of downstream gene expression may be an important component of pathophysiological responses to TBI.
Yang
K
K
Department of Neurosurgery, University of Texas Health Sciences Center at Houston 77030.
Mu
X S
XS
Xue
J J
JJ
Whitson
J
J
Salminen
A
A
dixon
C E
CE
Liu
P K
PK
Hayes
R L
RL
D000818:Animals; D001483:Base Sequence; D002540:Cerebral Cortex / Q000293:injuries* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D016762:Genes, fos; D006624:Hippocampus / Q000293:injuries / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018808:Transcription Factor AP-1 / Q000096:biosynthesis*
D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D018808:Transcription Factor AP-1