Gene expression homeostasis and chromosome architecture

Abstract

In rapidly growing populations of bacterial cells, including those of the model organism Escherichia coli, genes essential for growth - such as those involved in protein synthesis - are expressed at high levels; this is in contrast to many horizontally-acquired genes, which are maintained at low transcriptional levels.¹ This balance in gene expression states between 2 distinct classes of genes is established by a galaxy of transcriptional regulators, including the so-called nucleoid associated proteins (NAP) that contribute to shaping the chromosome.² Besides these active players in gene regulation, it is not too far-fetched to anticipate that genome organization in terms of how genes are arranged on the chromosome,³ which is the result of long-drawn transactions among genome rearrangement processes and selection, and the manner in which it is structured inside the cell, plays a role in establishing this balance. A recent study from our group has contributed to the literature investigating the interplay between global transcriptional regulators and genome organization in establishing gene expression homeostasis.⁴ In particular, we address a triangle of functional interactions among genome organization, gene expression homeostasis and horizontal gene transfer.

Keywords:

• gene expression
• chromosome architecture
• gene silencing
• horizontal gene transfer

This article refers to:

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

I thank Rajalakshmi Srinivasan, Vittore Scolari and Marco Cosentino Lagomarisino for contributing to the paper that eventually resulted in this commentary.

Funding

I thank the Department of Science and Technology (SERB) for supporting me through their Ramanujan Fellowship scheme (SR/S2/RJN-49/2010). Work on H-NS in our laboratory is supported by grants from the Department of Science and Technology (SERB; SB/SO/BB-0073/2012) and CEFIPRA (5103-3).