How the cells of your body become differentiated and perform different functions? How humans have become the most complex organisms so far discovered? What governs the ability of living organisms to respond to stimuli and to adapt to inhospitable environments? What makes life possible?
The answers to these questions fall on one of the most basic characteristic of living organisms, the regulation of gene expression. Cells with the same gene content can specialize and play distinct roles. In addition, external or internal stimuli can alter the function of a cell or even trigger systemic responses.
This cascade of changes undergone by cells during cellular differentiation, or before a stimulus is due to activation of genes that control other genes, whose activities are associated with activation or repression of various biological processes (replication, transcription, translation, cell death , DNA repair, cell cycle and energy production).
Until a few years ago, it was believed that the regulatory functions were performed by proteins through recognition of specific binding sites in DNA molecules. In recent decades, the role of non-coding RNAs (ncRNAs) in the regulation of gene expression was highlighted. The interaction of these molecules with proteins, DNA, mRNAs, forming distinct molecular complexes, allow ncRNAs act in different ways, which makes the regulatory networks increasingly intriguing and interesting to research. Thus, the study of regulation of gene expression has expanded its frontiers and it is increasingly clear that this important biological process can not be explained only by proteins or RNAs individually. This is a complex process, whose constituents should be studied all together, understanding their connections and their biological roles.
Storz, G., Opdyke, J. A., & Zhang, A. (2004). Controlling mRNA stability and translation with small, noncoding RNAs. Current Opinion in Microbiology
Wassarman, K. M., & Storz, G. (2011). Review Regulation by Small RNAs in Bacteria: Expanding Frontiers. Molecular Cell.