“Wolfe, these things aren’t even bacteria!!” It was about four decades ago when Carl Woese, a microbiologist working at the University of Illinois at Urbana told this to his colleague Ralph Wolfe. This turned out to be a finding that changed how we view evolution and the origins of life. Woese just discovered a new kind of organism that produces energy from the biosynthesis of methane whose rRNA fingerprint didn’t look like any other bacteria or eukaryote. Woese uncovered the third domain of life: Archaea.
Understanding the biology of these organisms might not only help explain their ability to adapt to different extreme environments, but also reconstruct evolutionary history. In this publication, scientists find a new mechanism of gene expression control in Archaea and reveal how the involved molecules interact with each other.
The mechanism behind an adaptive response to nutrient availability is unveiled
A quick way to modulate gene expression is by acting over already transcribed genes i.e. on mRNAs. This will determine whether the encoded protein will be produced or not and can be done by small non-coding RNAs (sRNAs), which is critical for rapid adaptive processes. Although several types of sRNAs have been identified in Archaea, not much is known about their regulatory roles.
The archaea Methanosarcina mazei has been found to differentially express a number of sRNAs depending on nitrogen availability on culture conditions, but their roles have remained a mystery and until targets were recently identified for one of them. In this study, binding analysis using MST verified the target of sRNA41 and lead to the discovery of a new mechanism for the post-transcriptional regulation in M. mazei that regulates the response to substrate availability. In particular, nitrogen availability actually tunes the expression of sRNA41, which in turn have an impact on energy metabolism and N2-fixation.