Moerman A M, Klein C
Cellular and Molecular Biology Graduate Training Program, Saint Louis University School of Medicine, Missouri 63104, USA.
Exp Cell Res. 1997 Nov 25;237(1):149-57. doi: 10.1006/excr.1997.3774.
We have examined the expression and heat inducibility of Hsp32, a novel small heat shock protein in Dictyostelium discoideum. Both Hsp32 and its mRNA are abundant in amoebae growing at physiological temperatures. Levels of Hsp32 remain high during the initial phases of development, including the formation of tipped mounds. After that stage, Hsp32 levels decrease, reaching barely detectable levels in culminating cells. In contrast, most of the hsp32 mRNA is rapidly degraded within the first few hours of starvation-induced development. Cells retain a new low steady state level of the mRNA throughout the rest of the developmental cycle. However, when cells undergo dedifferentiation, they reaccumulate high levels of hsp32 mRNA just prior to cell division. The heat inducibility of Hsp32 and its mRNA is maximal in growing cells and decreases as cells progress in their developmental program. The data suggest that Hsp32 is associated with a growth and/or survival function that is gradually eliminated during development.
我们研究了盘基网柄菌中一种新型小热休克蛋白Hsp32的表达及热诱导性。在生理温度下生长的变形虫中，Hsp32及其mRNA含量丰富。在发育的初始阶段，包括尖头丘的形成过程中，Hsp32水平保持较高。在该阶段之后，Hsp32水平下降，在终末分化细胞中降至几乎检测不到的水平。相比之下，大多数hsp32 mRNA在饥饿诱导发育的最初几个小时内迅速降解。在发育周期的其余阶段，细胞维持新的低稳态mRNA水平。然而，当细胞去分化时，它们在细胞分裂前重新积累高水平的hsp32 mRNA。Hsp32及其mRNA的热诱导性在生长细胞中最大，并随着细胞发育进程而降低。数据表明，Hsp32与一种在发育过程中逐渐消除的生长和/或存活功能相关。
