Theodorakis N G, Zand D J, Kotzbauer P T, Williams G T, Morimoto R I
Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208.
Mol Cell Biol. 1989 Aug;9(8):3166-73. doi: 10.1128/mcb.9.8.3166-3173.1989.
Hemin-induced differentiation of the human erythroleukemia cell line K562 results in the expression and accumulation of erythroid-specific gene products such as embryonic and fetal hemoglobins and the elevated synthesis of the major heat shock protein HSP70. This activity was suggested to represent activation of a heat shock gene during erythroid maturation independent of stress induction. In this study, we demonstrate that hemin induces the transcription of two members of the human HSP70 gene family, HSP70 and GRP78 (BiP). However, the induction of HSP70 by hemin showed characteristics consistent with the molecular events associated with a heat shock or stress response. The increase in HSP70 gene transcription was accompanied by induction of the stress-induced form of the heat shock transcription factor. Moreover, a heat shock element was required for the hemin responsiveness of chimeric heat shock promoter-chloramphenicol acetyltransferase genes transiently expressed in transfected K562 cells.
血红素诱导人红白血病细胞系K562分化，导致红系特异性基因产物的表达和积累，如胚胎血红蛋白和胎儿血红蛋白，同时主要热休克蛋白HSP70的合成增加。这种活性被认为代表红系成熟过程中热休克基因的激活，与应激诱导无关。在本研究中，我们证明血红素可诱导人HSP70基因家族的两个成员HSP70和GRP78（BiP）的转录。然而，血红素对HSP70的诱导表现出与热休克或应激反应相关分子事件一致的特征。HSP70基因转录的增加伴随着应激诱导形式的热休克转录因子的诱导。此外，在转染的K562细胞中瞬时表达的嵌合热休克启动子-氯霉素乙酰转移酶基因对血红素的反应性需要一个热休克元件。
