The flexibility of UV-inducible mutation in Deinococcus ficus as evidenced by the existence of the imuB–dnaE2 gene cassette and generation of superior feather degrading bacteria

Abstract

The lexA-imuB-dnaE2 gene cassette contributing to the TLS (translesion synthesis) polymerase activity and can easily cause mutation after DNA damage in many bacteria. But it was previously thought that TLS polymerase activity was unlikely to exist in the radio-resistant genus Deinococcus. In our preliminary studies, the lexA-imuB-dnaE2 gene cassette was found in a newly isolated feather-degrading Deinococcus ficus. Here we have attempted to determine the imuB gene sequence from another Deinococcus species namely D. grandis, by using the newly designed primers. The destroying of either imuB or dnaE2 gene in D. ficus leads to the increase in UV sensitivity and decrease in UV-induced mutations, which demonstrated the existence of TLS polymerase activity in D. ficus. In the presence of lexA-imuB-dnaE2, it is possible to obtain mutants with various keratinolytic activities after UV exposure. The keratinolytic activity of mutant strain CC-ZG207 increased by approximately twofold during growth in liquid feather medium. In contrast, the mutant strain CC-ZG227 showed only half of the keratinolytic activity compared with the wild type strain. By utilizing SDS-PAGE and zymogram profile analysis, the change in the protease activity was observed. We have proposed that the superior mutants of D. ficus can be created under UV stress, which is mediated by the lexA-imuB-dnaE2 gene cassette.

Transcriptional Responses of the Bacterium Burkholderia terrae BS001 to the Fungal Host Lyophyllum sp. Strain Karsten under Soil-Mimicking Conditions

“…2), was expressed throughout and then downregulated at the physical-contact stage with the fungus. Given that error-prone polymerases enhance mutagenesis under starvation stress [22, 23], this might suggest partial alleviation of starvation (or other) stress. Similarly, gene AKAUv1_3010006 (encoding a metallo-beta lactamase domain protein; function unknown) was also downregulated (log2 fold change −1.73).…”

Multiple Strategies for Translesion Synthesis in Bacteria

“…In Deinococcus ficus , a lexA - imuB - imuC gene cassette and a dinB2 gene are carried on an accessory plasmid [199]. Disruption of either imuB or imuC showed equal loss of survival and loss of mutagenesis following UV exposure, suggesting the same pathway of action for both survival and induced mutagenesis [199].…”

“…Disruption of either imuB or imuC showed equal loss of survival and loss of mutagenesis following UV exposure, suggesting the same pathway of action for both survival and induced mutagenesis [199]. Deinoccocus ficus naturally possesses keratinolytic activity to break down feathers, which could be used in agricultural and industrial applications [199]. Using the inherent mutator properties of ImuC, UV exposure was utilized as a mutagen to create improved keratinolytic activity [199].…”

“…Deinoccocus ficus naturally possesses keratinolytic activity to break down feathers, which could be used in agricultural and industrial applications [199]. Using the inherent mutator properties of ImuC, UV exposure was utilized as a mutagen to create improved keratinolytic activity [199]. Induced mutagenesis by UV light led to at least one mutant strain with a two-fold higher activity [199].…”

Extracellular peptidases from Deinococcus radiodurans

“…Basu and Apte (2008) reported the presence of a serralysin metalloprotease, and, recently, Are et al (2014) described a serine peptidase (APH; EC 3.4.19.1), which catalyzes the removal of an N-acylated amino acid from a blocked peptide. However, no work has been published concerning the presence of keratinases in D. radiodurans, despite the fact that Deinococcus ficus is described as a feather-degrading bacterium with the capability of enhancing the production of keratinase after UV inducible mutagenesis (Zeng et al 2011).…”