Cultured skin fibroblasts isolated from mice devoid of the prion protein gene express major heat shock proteins in response to heat stress.
Recent evidence has suggested that molecular chaperones participate in the conformational change between the normal cellular prion protein (PrPC) and its scrapie isoform (PrPSc). To study a role of PrPC in the regulation of expression of heat shock proteins (HSPs), a group of molecular chaperones, heat-induced expression of major HSPs (HSP105, HSP90alpha, HSP72, HSC70, HSP60, and HSP25) was investigated in cultured skin fibroblasts isolated from the mice homogeneous for a disrupted PrP gene (PrP-/- mice) by Western blot analysis and immunocytochemistry. Two lines of fibroblasts were established and designated SFK derived from the PrP-/- mice and SFH derived from the PrP+/+ mice, respectively. In both SFK and SFH cells, HSP105, HSP72, and HSP25 were expressed at low levels under unstressed conditions but they were induced markedly following exposure to heat stress (43 degreesC/20 min) at 3-72 h postrecovery. In both cell types, HSC70 and HSP60 were expressed at high levels under unstressed conditions and their levels remained unchanged after heat shock treatment. HSP90alpha was undetectable in both cell types under any conditions examined. The pattern of expression, induction, and subcellular location of HSP105, HSP72, HSC70, HSP60, and HSP25 was not significantly different between SFK and SFH cells under unstressed and heat-stressed conditions. Furthermore, the levels of constitutive expression of HSP105, HSC70, HSP60, and HSP25 were similar between the brain tissues isolated from the PrP-/- and PrP+/+ mice. These results indicate that HSP induction is not affected by either the existence or the absence of PrPC in the cells.
Satoh
J
J
Division of Neurology, Department of Internal Medicine, Saga Medical School, Saga, 849, Japan. satoj1@smsnet.saga-med.ac.jp
Yukitake
M
M
Kurohara
K
K
Nishida
N
N
Katamine
S
S
Miyamoto
T
T
Kuroda
Y
Y
D000818:Animals; D015153:Blotting, Western; D001923:Brain Chemistry / Q000502:physiology; D018834:Chaperonin 60 / Q000032:analysis / Q000235:genetics; D005347:Fibroblasts / Q000737:chemistry / Q000502:physiology; D015870:Gene Expression / Q000502:physiology; D050957:HSP110 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis / Q000235:genetics; D050884:HSP72 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins / Q000032:analysis / Q000235:genetics; D006360:Heat-Shock Proteins / Q000032:analysis / Q000235:genetics*; D006358:Hot Temperature; D051379:Mice; D018345:Mice, Knockout; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000032:analysis / Q000235:genetics; D011328:Prions / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D012867:Skin / Q000737:chemistry / Q000166:cytology*; D013312:Stress, Physiological / Q000235:genetics*
D018834:Chaperonin 60; D050957:HSP110 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D050884:HSP72 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; C490783:Hsp105 protein, mouse; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D011328:Prions; D012333:RNA, Messenger