Characterization of LeuO and additional LysR-type transcription regulators in Escherichia coli
Final Report Abstract
Transcription regulators are key players in the control of the genetic repertoire and the cellular response to changing conditions in all organisms. The bacterial ‘LysR’ type transcription regulators (LTTRs) studied in this project form the biggest family of transcription regulators. LTTRs bind specific DNA sequences with a high AT-content. Thus, LTTRs are prone regulators of horizontally acquired DNA (of higher AT-content than the core genome) and stress response genes. Some LTTRs play various roles in metabolic and stress response, but many others remain poorly characterized. We studied the LTTRs LeuO and YdcI among others in the E.coli K12 model organism. LeuO’s most effectively regulated target is the cas operon encoding the CRISPR-associated Cascade complex, one of the prokaryotic defense systems. Our results include the identification of LeuO’s consensus DNA-binding site and solving the crystal structure of its regulatory domain. Our data suggest that small structural changes in the regulatory domain significantly strengthen specific DNA binding. However, upon which trigger LeuO may activate the CRISPR-Cas defense remains elusive. For YdcI our data suggest that it is a phosphate starvation stress regulator, which is independent of the canonical phosphate stress response by PhoBR two-component signaling, and that YdcI controls genes encoding enzymes of TCA cycle and additional genes. Our data indicate that YdcI couples phosphate starvation and a a key metabolic pathway.
Publications
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Characterization of the pleiotropic LysR-type transcription regulator LeuO of Escherichia coli. Nucleic Acids Research, 47(14), 7363-7379.
Fragel, Susann M.; Montada, Anna; Heermann, Ralf; Baumann, Ulrich; Schacherl, Magdalena & Schnetz, Karin
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Deletion of FRT-sites by no-SCAR recombineering in Escherichia coli. Microbiology, 168(4).
Rangarajan, Aathmaja Anandhi; Yilmaz, Cihan & Schnetz, Karin
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High Abundance of Transcription Regulators Compacts the Nucleoid in Escherichia coli. Journal of Bacteriology, 204(6).
Yilmaz, Cihan & Schnetz, Karin
