- 作者: Joaquim Chan-Wang Lio; Wan-Jr Syu
- 作者服務機構: Institute of Microbiology and Immunology, Nationla Yang-Ming University, Taipei, Taiwan
- 中文摘要: --
- 英文摘要: Enterohemorrhagic Escherichia coli (EHEC) forms histo-logical lesions termed attaching and effacing lesions (W/Elesions) on infected large intestine tissue.The majorvirulence factors involved in A/E lesions reside on a locusof enterocyte effacement (LEE),a pathogenicity island.The LEE comprises 41 specific open reading frames, ofwhich most are organized in 5 major operons, LEE1,LEE2, LEE3, LEE4, and tir (LEE5). The expression of LEEgenes is regulated in a complicated manner by environ-mental factors such as temperature, osmolarity, andquorum sensing.Current knowledge is that regulation ishierarchical:a pivotal positive regulator, ler, is first stim-ulated,which in turn activates the expression of otheroperons. Herein,we report on the presence of a negativeregulation protein located within the LEE.L0044 is 372 bpin length and is located outside of the 5 major operons.An isogenic L0044 deletion mutant displayed loss of therepression phenotype and increased synthesis of severalLEE proteins when bacteria were cultured under repres-sive conditions that disfavor expression of LEE proteins.Reciprocally, trans expression of L0044 suppressed theexpression of the LEE.Furthermore, mRNA of ler in-creased as a result of deleting L0044, and disrupting lerin a L0044-deleted background reversed the loss of therepression phenotype.Thus, L0044 plays a role in regu-lating the expression of virulence genes in EHEC bymodulating the activation of ler.
- 中文關鍵字: --
- 英文關鍵字: --