Experimental data suggest that four billion years ago amino acids, purines and pyrimidines could be present in prebiotic soup. Non- enzymatic synthesis of peptides and RNA is possible. RNA can act as replicators and catalysts. Ribonucleic acids are very likely to be recognized as the molecules that gave rise to life. Riboorganisms used amino acids for the synthesis of purine and pyrimidine rings. They developed genetic code and translation. First proteins were used to create channels across phospholipid membranes and to stabilize ribozymes. Ribonucleoproteins containing catalytic RNA can be regarded as relicts from RNA World.
In eukaryotes, ribosomal 5S rRNAs are products of multigene families organized within clusters of tandemly repeated units. Accumulation of genomic data obtained from a variety of organisms demonstrated that the potential 5S rRNA coding sequences show a large number of variants, often incompatible with folding into a correct secondary structure. Here, we present results of an analysis of a large set of short RNA sequences generated by the next generation sequencing techniques, to address the problem of heterogeneity of the 5S rRNA transcripts in Arabidopsis and identification of potentially functional rRNA-derived fragments.
Pathogenic bacteria cause many diseases, some of which are fatal. For researchers, it is a challenge to understand bacterial mechanisms of pathogenicity, including their virulence pathways regulated by RNA. This work presents data on the mechanisms of regulation and expression of several virulence factors coded by RNA, namely 5' UTR fragments, riboswitches and small non-coding RNA (sRNA).
In recent years there was a growing number of reports of new non-protein-coding RNAs which are implicated in the regulation of many cellular processes. They differ in many respects from already known housekeeping RNA species involved in protein biosynthesis (tRNA, rRNA) and RNA maturation or modification (RNase P RNA, snRNAs, snoRNAs). Regulatory RNAs (riboregulators) are expressed only in certain cell types, at particular stages of organism development or cell differentiation or in response to biotic and abiotic stimuli. Their expression is usually accompanied by the alteration of patterns of the expression of other genes. The mechanisms employed by riboregulators can affect transcription, pre-mRNA processing and translation. In the post-genomic era, the noncoding regulatory RNAs emerge as key determinants of organismal complexity, providing efficient and highly specific means for integration of various cellular processes.
In the world of RNAs and proteins, similarities at the level of primary structures of two comparable molecules usually correspond to structural similarities at the tertiary level. In other words, measures of sequence and structure similarities are in general correlated - a high value of sequence similarity imposes a high value of structural similarity. However, important exceptions that stay in contrast to this general rule can be identified. It is possible to find similar structures with very different sequences, as well as similar sequences with very different structures. In this paper, we focus our attention on the latter case and propose a tool, called StructAnalyzer, supporting analysis of relations between the sequence and structure similarities. Recognition of tertiary structure diversity of molecules with very similar primary structures may be the key for better understanding of mechanisms influencing folding of RNAs or proteins, and as a result for better understanding of their function. StructAnalyzer allows exploration and visualization of structural diversity in relation to sequence similarity. We show how this tool can be used to screen RNA structures in Protein Data Bank (PDB) for sequences with structural variants.
National Center for Biotechnology Information (NCBI) gromadzi ogromne liczby danych opisujących różne organizmy biologiczne na wiele różnych sposobów. Dane te są przechowywane we właściwych bazach danych, zarządzanych przez NCBI. Baza danych GenBank jest jedną z najbardziej znanych na świecie baz NCBI przechowujących dziesiątki milionów sekwencji nukleotydowych DNA i RNA. W niniejszym artykule przedstawiono autorski system eksploracji danych genetycznych bazy GenBank. System search GenBank pozwala nie tylko wyszukiwać i przeglądać dane biologiczne bazy GenBank, ale także łączyć znalezione wpisy bazy GenBank z danymi w innych bazach danych NCBI, dając w ten sposób możliwość międzybazowej eksploracji danych.
EN
National Center for Biotechnology Information (NCBI) collects huge amounts of data describing various biological organisms in several ways. These data are stored in appropriate databases, managed by the NCBI. GenBank is one of the world's most famous NCBI database storing tens of millions of nucleotide sequences of DNA and RNA. In this article, we present a new system designed to explore genetic data in the GenBank database. The search GenBank system not only allows to search and browse biological data in the GenBank, but also combine the GenBank database entries with items in other NCBI databases. Therefore, the search GenBank provides the cross-database exploration possibilities.
Nucleic acid nanotechnology offers many methods to build self-assembled structures using RNA and DNA. These scaffolds are valuable in multiple applications, such as sensing, drug delivery and nanofabrication. Although RNA and DNA are similar molecules, they also have unique chemical and structural properties. RNA is generally less stable than DNA, but it folds into a variety of tertiary motifs that can be used to produce complex and functional nanostructures. Another advantage of using RNA over DNA is its ability to be encoded into genes and to be expressed in vivo. Here we review existing approaches for the self-assembly of RNA and DNA nanostructures and specifically methods to assemble large RNA structures. We describe de novo design approaches used in DNA nanotechnology that can be ported to RNA. Lastly, we discuss some of the challenges yet to be solved to build micron-scale, multi stranded RNA scaffolds.
In this review paper we discuss fatgraphs as a conceptual framework for RNA structures. We discuss various notions of coarse-grained RNA structures and relate them to fatgraphs.We motivate and discuss the main intuition behind the fatgraph model and showcase its applicability to canonical as well as noncanonical base pairs. Recent discoveries regarding novel recursions of pseudoknotted (pk) configurations as well as their translation into context-free grammars for pk-structures are discussed. This is shown to allow for extending the concept of partition functions of sequences w.r.t. a fixed structure having non-crossing arcs to pk-structures. We discuss minimum free energy folding of pk-structures and combine these above results outlining how to obtain an inverse folding algorithm for PK structures.