Induction of Apg-1, a member of the heat shock protein 110 family, following transient forebrain ischemia in the rat brain.
Apg-1 (Osp94) and apg-2 belong to the heat shock protein (hsp) 110 family. In mouse somatic cells the apg-1 and hsp105/110 transcripts are inducible by a 32 degrees C to 39 degrees C heat shock, while apg-2 is not heat-inducible. Since ischemia is known to induce expression of hsp70, its effect on expression of apg-1 was assessed by using the 20-min forebrain ischemia model of the rat. In the cerebral cortex, Northern blot analysis and in situ hybridization histochemistry demonstrated an increased expression in neuronal cells of apg-1 transcripts 3 h after the onset of reperfusion, with a peak at 12 h, followed by a decline. In the hippocampus, the level was increased at 3 h, remained constant until 24 h, and then declined. Transcript levels of apg-2 as well as hsp 105 were also increased under the present conditions, indicating that the expression of apg-2 was differentially regulated in response to heat and ischemic stresses. The induction kinetics of hsp 105, but neither apg-2 nor hsp 70, were identical to those of apg-1. These results demonstrated that brain ischemia/reperfusion induced expression of each member of the hsp 110 family, although the regulatory mechanisms may not be the same. They also suggest a significant role of apg-1 in both the ischemic- and heat-stress responses and in the normal functioning of the non-stressed neuronal cells.
Xue
J H
JH
Department of Clinical Molecular Biology, Graduate School of Pharmaceutical Sciences, Kyoto University, Japan.
Fukuyama
H
H
Nonoguchi
K
K
Kaneko
Y
Y
Kido
T
T
Fukumoto
M
M
Fujibayashi
Y
Y
Itoh
K
K
Fujita
J
J
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002545:Brain Ischemia / Q000503:physiopathology*; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000235:genetics*; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013696:Temperature
D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C490980:Hspa4l protein, rat; D012333:RNA, Messenger