Transcriptional activation of the htrA (High-temperature requirement A) gene from Bartonella henselae.
Transcriptional activation of the htrA (High-temperature requirement A) gene from Bartonella henselae.
复制标题
汉赛巴尔通体 htrA（高温要求 A）基因的转录激活。
DOI：
10.1128/iai.68.10.5970-5978.2000
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发表时间：
2000
影响因子：
3.1
通讯作者：
Anderson,BE
中科院分区：
文献类型：
--
作者：
Resto-Ruiz,SI;Sweger,D;Widen,RH;Valkov,N;Anderson,BE
BacterialhtrAgenes are typically activated as part of the periplasmic stress response and are dependent on the extracytoplasmic sigma factorrpoE. A putative promoter region, P1, of the ςE-type heat-inducible promoters has previously been identified upstream of thehtrAgene ofBartonella henselae. Further analysis of thehtrAmRNA by primer extension demonstrated that transcription initiates from P1 and a second region downstream of P1. This second promoter region, termed P2, had no sequence identity to ςE-type heat-inducible promoters. Promoter regions were cloned individually and in tandem into pANT3 upstream of a promoterless version of the green fluorescent protein (GFP) gene (gfpmut3) and transformed intoB. henselaeby electroporation. The contiguous promoter region containing both P1 and P2 were necessary for the optimal transcriptional activation of thehtrAgene. Promoter activity at 37°C was distinctively higher than at 27°C. However, thermal induction at 47°C did not increase expression ofgfpmut3. Invasion of human microvascular endothelial cells (HMEC-1) byB. henselaeresulted in the formation of well-defined vacuoles containing clusters of bacteria exhibiting marked expression ofgfpmut3transcribed from the P1-P2 region. In addition, a moderate yet significant increase in the ratio of bacterial GFP to DNA was detected for intracellular bacteria compared to extracellular bacteria, indicating upregulation ofhtrAupon invasion of HMEC-1. The activation of specific genes in the intracellular environment may help us better understand the novel pathogenic mechanisms used by this bacterium.
