The Sigma Factor AsbI Is Required for the Expression of Acinetobactin Siderophore Transport Genes in .

Int J Mol Sci

Departmento de Microbiología y Parasitología, Instituto de Acuicultura, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.

Published: June 2023


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Article Abstract

subsp. (), a Gram-negative bacterium causing furunculosis in fish, produces the siderophores acinetobactin and amonabactins in order to extract iron from its hosts. While the synthesis and transport of both systems is well understood, the regulation pathways and conditions necessary for the production of each one of these siderophores are not clear. The acinetobactin gene cluster carries a gene () encoding a putative sigma factor belonging to group 4 σ factors, or, the ExtraCytoplasmic Function (ECF) group. By generating a null mutant, we demonstrate that AsbI is a key regulator that controls acinetobactin acquisition in , since it directly regulates the expression of the outer membrane transporter gene and other genes necessary for Fe-acinetobactin transport. Furthermore, AsbI regulatory functions are interconnected with other iron-dependent regulators, such as the Fur protein, as well as with other sigma factors in a complex regulatory network.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10253897PMC
http://dx.doi.org/10.3390/ijms24119672DOI Listing

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