RNA silencing is described in plants and insects as a defence mechanism against foreign nucleic acids, such as invading viruses. The RNA silencing‑based antiviral defence involves the production of virus–derived small interfering RNAs and their association to effector proteins, which...

MicroRNA‑mediated modulation of translation has been recently discovered as a new dimension in gene expression regulation. In this chapter we review how this regulation operates in time between the fast protein modification and degradation steps on the one hand and the slow transcriptional...

Accumulating evidence over the last decade has presented us with the intriguing observation that the majority of eukaryotic genomes are pervasively transcribed to encode a complex network of small and long noncoding RNAs. Long noncoding RNAs are of particular interest, as they were once...

tRNA and tRNA processing enzymes impact more than protein production. Studies have uncovered roles for tRNA in the regulation of transcription, translation and protein turnover. Induced by stress or as a programmed part of development, nonrandom tRNA fragments can guide mRNA cleavage, inhibit...

Gene expression is a highly controlled process which is known to occur at several levels in eukaryotic organisms. Although messenger RNAs have been traditionally viewed as passive molecules in the pathway from transcription to translation, there is increasing evidence that their metabolism is...

RNA interference (RNAi) was initially discovered as a post‑transcriptional gene silencing mechanism in which short RNAs are used to target complementary RNAs for degradation. During the past several years, it has been demonstrated that RNAi‑related processes are also involved in...

The mRNA‑protein complexes (mRNPs, Messenger ribonucleoprotein particles) are the “couriers” of the modern eukaryotes that process, store and deliver messages (transcripts) from the nucleus to the appropriate subcellular compartments and beyond. Presence of mRNPs arbitrates the...

The majority of the human genome is found to be transcribed and generates mostly noncoding (nc) RNAs that do not possess protein information. MicroRNAs are one of the well‑identified small ncRNAs, but occupy merely a fraction of ncRNAs. Long (large) ncRNAs are emerging as a novel class of...

RNA silencing is a mechanism of genetic regulation that is mediated by short noncoding RNAs, or small RNAs (sRNAs). Regulatory interactions are established based on nucleotide sequence complementarity between the sRNAs and their targets. The development of new high‑throughput sequencing...

Noncoding RNAs form an indispensible component of the cellular information processing networks, a role that crucially depends on the specificity of their interactions among each other as well as with DNA and protein. Patterns of intramolecular and intermolecular base pairs govern most RNA...

The bacterial RNA network includes most of the same components found in eukaryotes, and many of the interactions that underlie transcription, RNA processing and stability, translation, and protein secretion are conserved. The major difference is that all of these functions take place in a...

The RNA infrastructure model highlights the major roles played by RNA–based networks in cellular biology. One of the principle concepts behind the RNA‑infrastructure is that proteins shared between RNP machineries network their processes in a temporal (over the cell cycle) and spatial...

Some major classes of RNAs (such as mRNA, rRNA, tRNA and RNase P) are ubiquitous in all living systems so are inferred to have arisen early during the origin of life. However, the situation is not so clear for the system of RNA regulatory networks that continue to be uncovered, especially in...

The RNA infrastructure connects RNA‑based functions. With transcription‑ to‑translation processing forming the core of the network, we can visualise how RNA‑based regulation, cleavage and modification are the backbone of cellular function. The key to interpreting the...

As with eukaryotes, prokaryotes employ a variety of mechanisms to allow the various types of RNA to interact and perform complex functions as a network. This chapter will detail prokaryotic molecular systems, such as riboswitches and CRISPRs, to show how they perform unique functions within...

It is becoming clear that in prokaryotes RNAs interact and perform complex functions as a network similar to what we have uncovered in eukaryotes. This chapter will continue the discussion of prokaryotic molecular systems, showing how these systems can interact with each other to gain a higher...

Gene expression is a highly controlled process which is known to occur at several levels in eukaryotic organisms. Although RNAs have been traditionally viewed as passive molecules in the pathway from transcription to translation, there is increasing evidence that their metabolism is controlled...