In Shigella flexneri and enteroinvasive Escherichia coli (EIEC) the expression of the virulence-plasmid(pINV)-carried potential pathogenesis-associated apy gene, which encodes apyrase (ATP diphosphohydrolase), is regulated by the same regulators that govern the expression of virulence genes. To understand the transcriptional organization of the apy gene, the authors sequenced an 8023 bp PstI fragment of the pINV of EIEC strain HN280, which encompasses apy as well as its adjacent genes. The PstI fragment displays 99% identity with the corresponding fragment of pWR100, the pINV of S. flexneri strain M90T, and contains four genes. One of these genes, ospB, encodes a secreted protein of unknown activity and is located immediately upstream of apy. Analyses of sequence, Northern hybridization, RT-PCR and primer extension data and transcriptional fusions indicated that ospB and apy are co-transcribed as a 2 kb bicistronic, temperature-regulated mRNA from an upstream promoter that precedes ospB. The 2 kb mRNA is post-transcriptionally processed in the intercistronic ospB–apy region, leading to the considerable accumulation of a more stable 1 kb apy-specific mRNA (half-life of 2<2O0<3 min, versus 27O4 s for the 2 kb transcript). Upon temperature induction, peak expression of the ospB–apy operon occurs when bacteria enter into the late phases of bacterial growth, where the apy-specific transcript was found to be much more prevalent if compared to the ospB–apy transcript.

Enteroinvasive Escherichia coli virulence plasmid-carried apyrase (apy) and ospB genes are organized as a bicistronic operon and are subject to differential expression.

NICOLETTI, Mauro
2002-01-01

Abstract

In Shigella flexneri and enteroinvasive Escherichia coli (EIEC) the expression of the virulence-plasmid(pINV)-carried potential pathogenesis-associated apy gene, which encodes apyrase (ATP diphosphohydrolase), is regulated by the same regulators that govern the expression of virulence genes. To understand the transcriptional organization of the apy gene, the authors sequenced an 8023 bp PstI fragment of the pINV of EIEC strain HN280, which encompasses apy as well as its adjacent genes. The PstI fragment displays 99% identity with the corresponding fragment of pWR100, the pINV of S. flexneri strain M90T, and contains four genes. One of these genes, ospB, encodes a secreted protein of unknown activity and is located immediately upstream of apy. Analyses of sequence, Northern hybridization, RT-PCR and primer extension data and transcriptional fusions indicated that ospB and apy are co-transcribed as a 2 kb bicistronic, temperature-regulated mRNA from an upstream promoter that precedes ospB. The 2 kb mRNA is post-transcriptionally processed in the intercistronic ospB–apy region, leading to the considerable accumulation of a more stable 1 kb apy-specific mRNA (half-life of 2<2O0<3 min, versus 27O4 s for the 2 kb transcript). Upon temperature induction, peak expression of the ospB–apy operon occurs when bacteria enter into the late phases of bacterial growth, where the apy-specific transcript was found to be much more prevalent if compared to the ospB–apy transcript.
File in questo prodotto:
File Dimensione Formato  
13 - Microbiology - 2002.pdf

Solo gestori archivio

Tipologia: Documento in Post-print
Dimensione 438.98 kB
Formato Adobe PDF
438.98 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11564/113604
Citazioni
  • ???jsp.display-item.citation.pmc??? 6
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 17
social impact