A Mur Regulator Protein in the Extremophilic Bacterium Deinococcus radiodurans

Abstract

Ferric uptake regulator (Fur) is a transcriptional regulator that controls the expression of genes involved in the uptake of iron and manganese, as well as vital nutrients, and is essential for intracellular redox cycling. We identified a unique Fur homolog (DR0865) from Deinococcus radiodurans, which is known for its extreme resistance to radiation and oxidants. A dr0865 mutant (Mt-0865) showed a higher sensitivity to manganese stress, hydrogen peroxide, gamma irradiation and ultraviolet (UV) irradiation than the wild-type R1 strain. Cellular manganese (Mn) ion (Mn2+) analysis showed that Mn2+, copper (Cu2+), and ferric (Fe3+) ions accumulated significantly in the mutant, which suggests that the dr0865 gene is not only involved in the regulation of Mn2+ homeostasis, but also affects the uptake of other ions. In addition, transcriptome profiles under MnCl2 stress showed that the expression of many genes involved in Mn metabolism was significantly different in the wild-type R1 and DR0865 mutant (Mt-0865). Furthermore, we found that the dr0865 gene serves as a positive regulator of the manganese efflux pump gene mntE (dr1236), and as a negative regulator of Mn ABC transporter genes, such as dr2283, dr2284 and dr2523. Therefore, it plays an important role in maintaining the homoeostasis of intracellular Mn (II), and also other Mn2+, zinc (Zn2+) and Cu2+ ions. Based on its role in manganese homeostasis, DR0865 likely belongs to the Mur sub-family of Fur homolog.

DqsIR quorum sensing‐mediated gene regulation of the extremophilic bacterium Deinococcus radiodurans in response to oxidative stress

“…Each suspension was divided in half: half was treated with 100 mM H 2 O 2 for 30 min, and the other half was incubated without treatment for the same length of time. Transcriptomic sequencing was performed using the Illumina Solexa high‐throughput sequencing platform (Ul Hussain Shah et al ., ).…”

The Cation Diffusion Facilitator Family Protein EmfA Confers Resistance to Manganese Toxicity in Brucella abortus 2308 and Is an Essential Virulence Determinant in Mice

“…Many bacteria require both Mn-responsive transcriptional regulators and Mn efflux proteins to maintain proper Mn homeostasis and prevent Mn toxicity (21,34,35). To date, Mur is the only Mn-responsive regulator that has been described in Brucella (23).…”

Recent progress in understanding the molecular mechanisms of radioresistance in Deinococcus bacteria

“…Fur family proteins generally act as repressors in the response to Fe(II), Mn(II), Zn(II) and Ni(II), referred to as Fur, Mur, Zur and Nur, respectively (Ahn et al 2006;Diaz-Mireles et al 2004;Ul Hussain Shah et al 2014;Fuangthong& Helman Fuangthong and Helmann 2003). Two Fur homologs have been described in D. radiodurans: PerR-like protein and dr0865, a Mur regulator protein.…”

“…A dr0865 mutant had a decreased survival rate after exposure to various stress factors, such as manganese stress, hydrogen peroxide and gamma and UV irradiation than the wild-type R1 strain. Dr0865 gene regulates the manganese efflux pump gene mntE and Mn ABC transporter genes, and plays an important role in preserving the homeostasis of intracellular Mn 2+ (Ul Hussain Shah et al 2014).…”