Specialized cellular compartments discovered in bacteria
Discovery of bacterial 'organs' could pave the way for a new generation
of antibiotics

Date:
July 20, 2020
Source:
McGill University
Summary:
Researchers have discovered bacterial organelles involved in gene
expression, suggesting that bacteria may not be as simple as once
thought. This finding could offer new targets for the development
of new antibiotics.



FULL STORY ========================================================================== Researchers at McGill University have discovered bacterial organelles
involved in gene expression, suggesting that bacteria may not be as
simple as once thought. This finding could offer new targets for the development of new antibiotics.


==========================================================================
The study, published in Proceedings of the National Academy of Sciences,
is the first to show that E. coli uses similar strategies to regulate
gene transcription as other more complex cell types.

Just like the human body is made up of organs that perform specialized functions, individual cells contain specialized compartments -- such as
energy- producing mitochondria -- called organelles. Complex cells contain
many different organelles, most of which are enclosed by a membrane
that holds them together. Because bacteria do not have membrane-bound organelles, they were assumed to lack them altogether.

Stephanie Weber, an assistant professor in McGill's Department of Biology,
and her team are the first to show that bacteria do in fact have such specialized compartments.

"Our paper provides evidence for a bacterial organelle that is held
together by "sticky" proteins rather than a membrane," says Weber,
who is the study's senior author.

The bacterial organelles described in the study are formed in a similar
fashion to membraneless cellular compartments found in more complex
eukaryotic cells (cells with a nucleus) through a process called phase separation, the same phenomenon that causes oil and vinegar to separate
in salad dressing.

"This is the first direct evidence of phase separation in bacteria,
so it may be a universal process in all cell types, and could even have
been involved in the origin of life," explains Weber.

Because of the small size of the bacterial cells they were studying,
Weber's team used an imaging technique -- photo activated localization microscopy -- to track the organelle-forming proteins.

Weber is now trying to understand exactly how the proteins assemble into organelles. Because they're involved in the first steps of gene expression
- - transcription -- she believes they might also be an interesting
target for the development of a new generation of antibiotic drugs,
which are urgently needed to combat drug resistance.


========================================================================== Story Source: Materials provided by McGill_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Anne-Marie Ladouceur, Baljyot Singh Parmar, Stefan Biedzinski, James
Wall, S. Graydon Tope, David Cohn, Albright Kim, Nicolas Soubry,
Rodrigo Reyes-Lamothe, Stephanie C. Weber. Clusters of bacterial
RNA polymerase are biomolecular condensates that assemble through
liquid-liquid phase separation. Proceedings of the National Academy
of Sciences, 2020; 202005019 DOI: 10.1073/pnas.2005019117 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200720103324.htm

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