Induction of gene expression in Dictyostelium by prestarvation factor, a factor secreted by growing cells.
Induction of gene expression in Dictyostelium by prestarvation factor, a factor secreted by growing cells.
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DOI：
10.1002/dvg.1020120115
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
A. Rathi;S. Kayman;M. Clarke
中科院分区：
文献类型：
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作者：
A. Rathi;S. Kayman;M. Clarke
在生长过程中，盘基骨柱细胞不断分泌一种因子，PSF，该因子的积累与细胞密度成正比。在足够的浓度下，它触发盘状蛋白I和某些溶酶体酶的产生。我们早期的研究证实了PSF对蛋白质和酶水平的影响[Clarke et al., Differentiation 34:79- 87,1987；[j].中国生物医学工程学报（英文版），2002。在本研究中，我们研究了PSF是否诱导mRNA水平升高。通过Northern blot分析，我们发现随着NC4细胞达到高密度，呈指数增长的细胞中diskidin I mRNA积累；在培养皿或悬浮中生长的细胞中，在指数生长结束前约四代开始检测到显著水平的mRNA。在高密度细胞调节的缓冲液中生长的低密度细胞中也发现了高水平的盘状蛋白I mRNA。这些结果表明，PSF诱导盘状蛋白I mRNA的积累。其他“早期发育”基因，pCZ22和早期I基因（16,18和111），也在高密度或条件缓冲液存在下的指数生长细胞中表达。我们得出结论，先前发现的几个在发育早期优先表达的基因实际上是在PSF的指数生长后期诱导的。
During growth, Dictyostelium cells continuously secrete a factor, PSF, that accumulates in proportion to cell density. At sufficient concentration, it triggers the production of discoidin I and certain lysosomal enzymes. Our earlier studies demonstrated these effects of PSF on protein and enzyme levels [Clarke et al., Differentiation 34:79-87, 1987; Clarke et al., Dev Genet 9: 315-326, 1988]. In the present study, we have examined whether PSF induces increased mRNA levels. By Northern blot analysis, we have found that discoidin I mRNA accumulates in exponentially growing NC4 cells as the cells reach high density; significant levels of mRNA are detectable in cells growing either on plates or in suspension, beginning about four generations before the end of exponential growth. High levels of discoidin I mRNA are also found in low-density cells grown in the presence of buffer conditioned by high-density cells. These results indicate that PSF induces the accumulation of discoidin I mRNA. Other "early developmental" genes, pCZ22 and the early I genes (16, 18, and 111), are also expressed in exponentially growing cells at high density or in the presence of conditioned buffer. We conclude that several genes previously found to be preferentially expressed very early in development are actually induced during late exponential growth by PSF.