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Screening Foodstuffs for Class 1 Integrons and Gene Cassettes
Published on: June 19, 2015
Pc promoter from class 2 integrons and the cassette transcription pattern it evokes
Érica Lourenço da Fonseca1, Fernanda dos Santos Freitas, Ana Carolina Paulo Vicente
1Laboratório de Genética Molecular de Microrganismos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil. ericafan@ioc.fiocruz.br
The Journal of Antimicrobial Chemotherapy
|March 12, 2011
Summary
This study characterized the Pc promoter in class 2 integrons, revealing its role in driving gene cassette transcription. Findings demonstrate that gene cassette position influences transcription levels, with proximal cassettes exhibiting higher expression.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Integrons function as gene expression systems driven by Pc promoters.
- Pc promoter characteristics are established for class 1 integrons but remain uncharacterized for class 2 integrons.
Purpose of the Study:
- To characterize the Pc promoter in class 2 integrons.
- To investigate the impact of gene cassette position on transcription driven by the class 2 Pc promoter.
Main Methods:
- Sequencing of class 2 cassette arrays from Klebsiella pneumoniae and Vibrio cholerae.
- Real-time RT-PCR for transcription analysis and relative quantification of gene transcripts.
- 5' rapid amplification of cDNA ends and in silico promoter prediction for Pc promoter characterization.
Main Results:
- Identified dfrA1-sat2-aadA1-ybeA and sat2-aadA1-ybeA arrangements in K. pneumoniae and V. cholerae.
- Demonstrated higher transcription of proximal gene cassettes compared to distal ones.
- Characterized the class 2 Pc promoter sequence (-35 TTTAAT |16 bp| -10 TAAAAT) and confirmed cassette expression through antibiotic resistance profiles.
Conclusions:
- The Pc promoter of class 2 integrons was characterized for the first time.
- A significant effect of gene cassette position on transcription levels was established.
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