Abstract
The structure and dynamics of bacterial nucleoids play important roles in regulating gene expression. Bacteria of class Mollicutes and, in particular, mycoplasmas feature extremely reduced genomes. They lack multiple structural proteins of the nucleoid, as well as regulators of gene expression. We studied the organization of Mycoplasma gallisepticum nucleoids in the stationary and exponential growth phases at the structural and protein levels. The growth phase transition results in the structural reorganization of M. gallisepticum nucleoid. In particular, it undergoes condensation and changes in the protein content. The observed changes corroborate with the previously identified global rearrangement of the transcriptional landscape in this bacterium during the growth phase transition. In addition, we identified that the glycolytic enzyme enolase functions as a nucleoid structural protein in this bacterium. It is capable of non-specific DNA binding and can form fibril-like complexes with DNA.
Highlights
Bacterial nucleoid structure and function are maintained by a set of proteins, including structural proteins that organize DNA loops, proteins that maintain negative supercoiling of DNA, RNA polymerase (RNAP), transcription factors and proteins that facilitate nucleoid separation into daughter cells during cell division
The nucleoid structure and its dynamics represent an important part of global gene expression regulation
The integration of the known data for regulatory networks in Escherichia coli demonstrates that nucleoid structural proteins may serve as high-level nodes in regulatory networks (Martínez-Antonio and Collado-Vides, 2003)
Summary
Bacterial nucleoid structure and function are maintained by a set of proteins, including structural proteins that organize DNA loops, proteins that maintain negative supercoiling of DNA, RNA polymerase (RNAP), transcription factors and proteins that facilitate nucleoid separation into daughter cells during cell division. The nucleoid structure and its dynamics represent an important part of global gene expression regulation. The phenomenon of liquid-liquid phase separation (LLPS) of NAPs is another example of nucleoid structure dynamics that globally regulates gene expression. Nucleoid structural proteins can preferentially bind to DNA with a certain degree of supercoiling or bending. The data obtained helped to reveal the structure of the chromosome-interacting domains with 10 kb resolution Their size ranged from 15 to 33 kb and genes within the same domain showed a tendency to co-regulate. Obtained transcriptomic data indicate that M. gallisepticum undergoes global rearrangement of the transcriptional landscape depending on the growth phase (Mazin et al, 2014). To reveal the underlying mechanisms, we studied the structure and protein composition of the M. gallisepticum nucleoid during the exponential and stationary growth phases
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
