Landsberger N, Ranjan M, Almouzni G, Stump D, Wolffe A P
Laboratory of Molecular Embryology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
Dev Biol. 1995 Jul;170(1):62-74. doi: 10.1006/dbio.1995.1195.
The heat shock response in Xenopus laevis has been reported to be developmentally regulated at the transcriptional level. We find that the heat shock response of an exogenous Xenopus hsp70 gene introduced into Xenopus oocytes, embryos, and somatic cells is dependent on the transcriptional assay conditions employed. Under conditions of efficient chromatin assembly, transcription from the Xenopus hsp70 gene promoter is repressed in oocytes and embryos, yet the promoter responds to heat shock by activating transcription. Under conditions of inefficient chromatin assembly, the Xenopus hsp70 gene is constitutively active in oocytes and somatic cells. Our results resolve previous controversy concerning the existence of a heat shock response for the hsp70 promoter in oocytes and illustrate the importance of considering chromatin assembly as a contributory factor in reconstructing the developmental control of gene expression.
据报道，非洲爪蟾的热休克反应在转录水平上受到发育调控。我们发现，导入非洲爪蟾卵母细胞、胚胎和体细胞中的外源非洲爪蟾hsp70基因的热休克反应取决于所采用的转录分析条件。在高效染色质组装的条件下，非洲爪蟾hsp70基因启动子的转录在卵母细胞和胚胎中受到抑制，但该启动子通过激活转录对热休克作出反应。在染色质组装效率低下的条件下，非洲爪蟾hsp70基因在卵母细胞和体细胞中组成性激活。我们的结果解决了先前关于卵母细胞中hsp70启动子热休克反应存在与否的争议，并说明了在重建基因表达的发育控制过程中，将染色质组装视为一个促成因素的重要性。
