Banerji S S, Laing K, Morimoto R I
Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60201.
Genes Dev. 1987 Nov;1(9):946-53. doi: 10.1101/gad.1.9.946.
We have studied the expression of the major heat shock protein HSP70 during maturation of avian erythroid cells. Primitive and definitive erythroid cells were isolated from staged day 3-8 chicken embryos, and the levels of HSP70 mRNA and protein synthesis were examined. The highest levels of HSP70 are detected in polychromatic cells of the day 3-4 primitive erythroid cell. After the initial burst of HSP70 expression the levels of HSP70 mRNA and protein synthesis decline. Although HSP70 is constitutively expressed, neither HSP70 synthesis nor HSP70 mRNA levels were heat shock inducible in primitive red cells. In contrast, definitive red cells respond to heat shock by a 10- to 20-fold increase in HSP70 protein synthesis with little change in HSP70 mRNA levels. These studies reveal that HSP70 expression in erythroid cells is lineage specific, that the levels of HSP70 mRNA are not induced by heat shock, and finally, that the increased expression of HSP70 in definitive cells is due to increased translatability of HSP70 mRNA.
我们研究了主要热休克蛋白HSP70在禽类红细胞成熟过程中的表达。从第3至8天不同发育阶段的鸡胚胎中分离出原始红细胞和成熟红细胞，并检测了HSP70 mRNA水平和蛋白质合成情况。在第3至4天原始红细胞的多色细胞中检测到最高水平的HSP70。在HSP70表达的初始爆发之后，HSP70 mRNA水平和蛋白质合成下降。虽然HSP70是组成性表达，但在原始红细胞中，HSP70合成及HSP70 mRNA水平均不受热休克诱导。相比之下，成熟红细胞对热休克的反应是HSP70蛋白质合成增加10至20倍，而HSP70 mRNA水平变化不大。这些研究表明，红细胞中HSP70的表达具有谱系特异性，HSP70 mRNA水平不受热休克诱导，最后，成熟细胞中HSP70表达增加是由于HSP70 mRNA的翻译能力增强。
