Fig. 4. DNA binding activity of HIF-1 in Z. viviparus whole cell extracts
from the liver after 2 h of exposure to 18°, 22° and 26°C and
after 24 h recovery (recov.) from these temperatures. (A) Signal intensity of
HIF-1 DNA binding to the human erythropoietin enhancer. Lanes 1: unstressed;
2: 1°C; 3: 1°C recovery; 4: 5°C; 5: 5°C recovery; 6: 18°C;
7: 18°C recovery; 8: 22°C; 9: 22°C recovery; 10: 26°C; 11:
26°C recovery; data taken from the heat stress experiment (this study) and
from cold stress (K. Heise, S. Puntarulo, M. Nikinmaa, M. Lucassen, H.-O.
Pörtner and D. Abele, unpublished data). (B) HIF-1 DNA binding. Values
are means ± s.d., N=4-5; *significantly different
from the unstressed group, P<0.05. (C) Linear regression
demonstrating increased HIF-1 DNA binding at a more reduced redox environment
(y=0.065x-7.593; r2=0.3, N=50,
P<0.05, Statview 5.0). Data taken from the heat stress experiment
(this study) and from cold stress (K. Heise, S. Puntarulo, M. Nikinmaa, M.
Lucassen, H.-O. Pörtner and D. Abele, unpublished data).