Shakoori A R, Oberdorf A M, Owen T A, Weber L A, Hickey E, Stein J L, Lian J B, Stein G S
Department of Cell Biology, University of Massachusetts Medical Center, Worcester 01655.
J Cell Biochem. 1992 Mar;48(3):277-87. doi: 10.1002/jcb.240480308.
The progressive differentiation of both normal rat osteoblasts and HL-60 promyelocytic leukemia cells involves the sequential expression of specific genes encoding proteins that are characteristic of their respective developing cellular phenotypes. In addition to the selective expression of various phenotype marker genes, several members of the heat shock gene family exhibit differential expression throughout the developmental sequence of these two cell types. As determined by steady state mRNA levels, in both osteoblasts and HL-60 cells expression of hsp27, hsp60, hsp70, hsp89 alpha, and hsp89 beta may be associated with the modifications in gene expression and cellular architecture that occur during differentiation. In both differentiation systems, the expression of hsp27 mRNA shows a 2.5-fold increase with the down-regulation of proliferation while hsp60 mRNA levels are maximal during active proliferation and subsequently decline post-proliferatively. mRNA expression of two members of the hsp90 family decreases with the shutdown of proliferation, with a parallel relationship between hsp89 alpha mRNA levels and proliferation in osteoblasts and a delay in down-regulation of hsp89 alpha mRNA levels in HL-60 cells and of hsp89 beta mRNA in both systems. Hsp70 mRNA rapidly increases, almost twofold, as proliferation decreases in HL-60 cells but during osteoblast growth and differentiation was only minimally detectable and showed no significant changes. Although the presence of the various hsp mRNA species is maintained at some level throughout the developmental sequence of both osteoblasts and HL-60 cells, changes in the extent to which the heat shock genes are expressed occur primarily in association with the decline of proliferative activity. The observed differences in patterns of expression for the various heat shock genes are consistent with involvement in mediating a series of regulatory events functionally related to the control of both cell growth and differentiation.
正常大鼠成骨细胞和HL - 60早幼粒细胞白血病细胞的渐进分化涉及特定基因的顺序表达，这些基因编码的蛋白质是其各自发育中细胞表型的特征。除了各种表型标记基因的选择性表达外，热休克基因家族的几个成员在这两种细胞类型的整个发育序列中表现出差异表达。根据稳态mRNA水平测定，在成骨细胞和HL - 60细胞中，hsp27、hsp60、hsp70、hsp89α和hsp89β的表达可能与分化过程中发生的基因表达和细胞结构的改变有关。在这两种分化系统中，hsp27 mRNA的表达随着增殖的下调而增加2.5倍，而hsp60 mRNA水平在活跃增殖期间最高，随后在增殖后下降。hsp90家族的两个成员的mRNA表达随着增殖的停止而降低，在成骨细胞中hsp89α mRNA水平与增殖之间存在平行关系，在HL - 60细胞中hsp89α mRNA水平的下调延迟，在这两种系统中hsp89β mRNA也是如此。随着HL - 60细胞增殖减少，hsp70 mRNA迅速增加近两倍，但在成骨细胞生长和分化过程中仅能检测到微量，且无显著变化。尽管在成骨细胞和HL - 60细胞的整个发育序列中，各种hsp mRNA种类在一定水平上保持存在，但热休克基因表达程度的变化主要与增殖活性的下降有关。观察到的各种热休克基因表达模式的差异与参与介导一系列与细胞生长和分化控制功能相关的调节事件一致。
