Title |
Functional characterization of HigBA toxin-antitoxin system in an Arctic bacterium, Bosea sp. PAMC 26642 |
Author |
Eunsil Choi1,2, Ahhyun Huh1, Changmin Oh1, Jeong-Il Oh1,2, Ho Young Kang1,2, and Jihwan Hwang1,2* |
Address |
1Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea, 2Microbiological Resource Research Institute, Pusan National University, Busan 46241, Republic of Korea |
Bibliography |
Journal of Microbiology, 60(2),192-206, 2022,
|
DOI |
10.1007/s12275-022-1619-9
|
Key Words |
toxin-antitoxin system, HigBA, endoribonuclease,
Bosea, translation inhibition |
Abstract |
Toxin-antitoxin (TA) systems are growth-controlling genetic
elements consisting of an intracellular toxin protein and its
cognate antitoxin. TA systems have been spread among microbial
genomes through horizontal gene transfer and are
now prevalent in most bacterial and archaeal genomes. Under
normal growth conditions, antitoxins tightly counteract the
activity of the toxins. Upon stresses, antitoxins are inactivated,
releasing activated toxins, which induce growth arrest or cell
death. In this study, among nine functional TA modules in
Bosea sp. PAMC 26642 living in Arctic lichen, we investigated
the functionality of BoHigBA2. BohigBA2 is located close to
a genomic island and adjacent to flagellar gene clusters. The
expression of BohigB2 induced the inhibition of E. coli growth
at 37°C, which was more manifest at 18°C, and this growth
defect was reversed when BohigA2 was co-expressed, suggesting
that this BoHigBA2 module might be an active TA
module in Bosea sp. PAMC 26642. Live/dead staining and
viable count analyses revealed that the BoHigB2 toxin had
a bactericidal effect, causing cell death. Furthermore, we demonstrated
that BoHigB2 possessed mRNA-specific ribonuclease
activity on various mRNAs and cleaved only mRNAs
being translated, which might impede overall translation and
consequently lead to cell death. Our study provides the insight
to understand the cold adaptation of Bosea sp. PAMC 26642
living in the Arctic. |