The role of Sig1 in the stress response of the Gram-positive microbe - Deinococcus radiodurans

Alternative sigma factor Sig1 confers extensive resistance against heat, cold, ethanol and oxidative stress to D. radiodurans. Our aim is to find the activation of Sig1 and its regulons under these harsh conditions and delineate the Sig1-mediated regulatory network.

More recently, scientists have begun using D. radiodurans as a new chassis for industrial biotechnology due to its specific ability to grow and express novel engineered functions. As expected, D. radiodurans makes it a possible to build industrial strains that is able to use organic wastes more efficiently and with improved tolerance to various abiotic and biotic stresses. However, the physiology and ecology of D. radiodurans, including the regulatory circuits involved in its stress resilience, is are not in better yet fully understanding understood and this organism’s coping strategies against harsh conditions are not clearly elucidated until now, currently limiting our ability to fully harness its unique ability to cope with extreme environmental conditions. 

D. radiodurans is called a poly-extremophile, which is not exclusive to radiation, desiccation and oxidation but extends also to a variety of additional adverse conditions. Nevertheless, previous studies are mainly focusing on D. radiodurans radio-resistance and rarely attaching giving attention on to its multi-resistance. Genomic analysis and fundamental experiments indicated that there are many more functional elements awaiting to be characterized, which shows highly relevant to  in order to fully comprehend and exploit its multiple resistance.

Our current research showed that Sig1, the only one alternative sigma factor in D. radiodurans, was identified as a multifunctional regulator conferring the resistance against a variety of stresses, including extreme temperatures (heat & cold), high concentration of ethanol, and oxidative stress. Hence, it is essential to study the role and response of Sig1 and its regulatory mechanisms under different stresses.

The role of Sig1 in the stress response of the Gram-positive microbe - Deinococcus radiodurans