Airaksinen Susanna, Råbergh Christina M I, Lahti Anna, Kaatrasalo Annukka, Sistonen Lea, Nikinmaa Mikko
Department of Biology, Laboratory of Animal Physiology, University of Turku, FIN-20014 Turku, Finland.
Comp Biochem Physiol A Mol Integr Physiol. 2003 Apr;134(4):839-46. doi: 10.1016/s1095-6433(03)00033-3.
Heat shock transcription factors (HSFs) regulate expression of heat shock proteins (Hsps). We have previously shown that in zebrafish a unique isoform, zHSF1b, disappears concomitant with heat shock-induced Hsp70 expression. To characterize the role of zHSF1a and zHSF1b isoforms in the regulation of the stress response in vivo, we have carried out cadmium (10-100 microM) and copper (10-30 microM) exposures in order to specify whether the disappearance of HSF1b is specific for heat stress. After 4-h metal exposures we analyzed the expression of hsp70, zHSF1a, zHSF1b and metallothionein (MT) by reverse transcriptase polymerase chain reaction in zebrafish liver, gonads and gills. Although cadmium is a known inducer of Hsps, it did not affect hsp70 expression significantly in the studied tissues. Induction of hsp70 was observed upon copper exposure in liver and gonads, but not in gills. Neither metal affected the zHSF1a/b ratio. Both cadmium and copper exposure caused upregulation of MT, regulator of metal homeostasis and detoxification, confirming that the tissues were subjected to metal loads. Thus, hsp70 appears to be more weakly induced upon metal exposure than in response to heat shock and HSF1 isoforms may participate in stressor-specific regulation of hsp70.
热休克转录因子（HSFs）调节热休克蛋白（Hsps）的表达。我们之前已经表明，在斑马鱼中，一种独特的异构体zHSF1b会随着热休克诱导的Hsp70表达而消失。为了表征zHSF1a和zHSF1b异构体在体内应激反应调节中的作用，我们进行了镉（10 - 100微摩尔）和铜（10 - 30微摩尔）暴露实验，以确定HSF1b的消失是否特定于热应激。在4小时金属暴露后，我们通过逆转录聚合酶链反应分析了斑马鱼肝脏、性腺和鳃中hsp70、zHSF1a、zHSF1b和金属硫蛋白（MT）的表达。尽管镉是已知的Hsps诱导剂，但在研究的组织中它对hsp70表达没有显著影响。在肝脏和性腺中铜暴露后观察到hsp70的诱导，但在鳃中未观察到。两种金属都不影响zHSF1a/b的比例。镉和铜暴露均导致金属稳态和解毒调节因子MT的上调，证实组织受到了金属负荷。因此，与热休克相比，金属暴露时hsp70的诱导似乎较弱，并且HSF1异构体可能参与hsp70的应激源特异性调节。
