Arnau J, Sørensen K I, Appel K F, Vogensen F K, Hammer K
Department of Dairy and Food Science, Royal Veterinary and Agricultural University, Frederiksberg, Denmark.
Microbiology (Reading). 1996 Jul;142 ( Pt 7):1685-91. doi: 10.1099/13500872-142-7-1685.
The induction of the heat shock response in Lactococcus lactis subsp. cremoris strain MG1363 was analysed at the RNA level using a novel RNA isolation procedure to prevent degradation. Cloning of the dnaJ and groEL homologues was carried out. Northern blot analysis showed a similar induction pattern for dnaK, dnaJ and groELS after transfer from 30 degrees C to 43 degrees C when MG1363 was grown in defined medium. The dnaK gene showed a 100-fold induction level 15 min after temperature shifting. Induction of the first two genes in the dnaK operon, orf1 and grpE, resembled the pattern observed for the above genes, although maximum induction was observed earlier for orf1 and grpE. Novel transcript sizes were detected in heat-shocked cells. The induction kinetics observed for ftsH suggested a different regulation for this gene. Experimental evidence for a pronounced transcriptional regulation being involved in the heat shock response in L. lactis MG1363 is presented. A gene located downstream of the dnaK operon in strain MG1363, named orf4, was shown not to be regulated by heat shock.
采用一种新型RNA分离程序防止降解，在RNA水平上分析了乳酸乳球菌乳脂亚种MG1363中热休克反应的诱导情况。进行了dnaJ和groEL同源物的克隆。当MG1363在限定培养基中生长时，从30℃转移至43℃后，Northern印迹分析显示dnaK、dnaJ和groELS呈现相似的诱导模式。温度转移15分钟后，dnaK基因显示出100倍的诱导水平。dnaK操纵子中的前两个基因orf1和grpE的诱导情况与上述基因相似，尽管orf1和grpE的最大诱导出现在更早的时候。在热休克细胞中检测到了新的转录本大小。ftsH的诱导动力学表明该基因存在不同的调控方式。本文提供了乳酸乳球菌MG1363热休克反应中存在明显转录调控的实验证据。MG1363菌株中位于dnaK操纵子下游的一个名为orf4的基因，显示不受热休克调控。
