细胞技术

Microbodies™ are novel pharmacophoric entities which are derived from naturally occurring cystine-knot microproteins. They provide extremely stable scaffolds that can be engineered to high-affinity binding proteins. A peptide-grafting approach yielded specific liga ...

Riboswitches are RNA elements capable of modulating gene expression through interaction with cellular metabolites. One member of the riboswitch family, the glmS riboswitch, is unique among riboswitches in that it modulates gene expression by undergoing self-cleavage in the pres ...

RNA sequences fold upon themselves to form complex structures. Functional analysis of most biological RNAs requires knowledge of secondary structure arrangements and tertiary base interactions. Therefore, rapid and comprehensive methods for assessing RNA structure are hi ...

A detailed understanding of cellular mechanisms requires knowledge of structure and dynamics of the involved biomacromolecules at atomic resolution. NMR spectroscopy uniquely allows determination of static and dynamic processes at atomic level, including structured sta ...

Riboswitches are functional RNA molecules that control gene expression through conformational changes in response to small-molecule ligand binding. In addition, riboswitch 3D structure, like that of other RNA molecules, is dependent on cation–RNA interactions as the RNA backbo ...

Procedures that were critical for crystallization of the glmS ribozyme-riboswitch RNA domain from the thermophilic Gram-positive bacterium Thermoanaerobacter tengcongensis are described. Experimental design based on screening multiple variant RNA sequences and te ...

The versatility of RNA as a regulatory molecule has become increasingly apparent in recent years. RNA elements within a transcript can sense a large variety of physiological signals, resulting in modulation of expression of the gene(s) encoded on that transcript by effects on transcript sy ...

Enzymatic probing and lead(II)-induced cleavages have been developed to study the secondary structure of RNA molecules either free or engaged in complex with different ligands. Using a combination of probes with different specificities (unpaired vs. paired regions), it is possible to ...

Toeprinting was developed to study the formation of ribosomal initiation complexes in bacteria. This approach, based on the inhibition of reverse transcriptase elongation, was used to monitor the effect of ribosomal components and translational factors on the formation of the acti ...

Chemical probing of RNA structure has become one of the most popular approaches to map the conformation of RNA molecules of various sizes under well-defined experimental conditions. The method monitors the sensitivity of each nucleotide to various chemicals, which reflects its hydro ...

The heat shock (HS) response is the major cellular defense mechanism against acute exposure to environmental stresses. The hallmark of the HS response, which is conserved in all eukaryotes, is the rapid and massive induction of expression of a set of cytoprotective genes. Most of the induction o ...

Riboswitches are vital components of many genomes. Covariance model searches for the characteristic architectures of riboswitch aptamer domains can be used to predict new examples of these structured RNAs. Since riboswitches generally function as cis-regulatory elements, ex ...

Riboswitches are non-coding RNA elements mainly located in the 5′ untranslated regions (UTR) of bacterial genes. They bind to small metabolites and upon binding conformational changes occur that trigger the expression of a certain gene. Riboswitches have been identified that bind to am ...

Regulation of gene expression in bacteria by cis-acting RNA elements can be investigated both in vivo and in vitro. Analyses in vivo can focus on changes in mRNA transcript levels or in protein production. Systems that are regulated at the level of premature termination of transcription are best ...

Small non-coding RNAs (sRNAs) are an emerging class of regulators of bacterial gene expression, which mainly modulate the translation of trans-encoded mRNAs. Typically, these molecules are 50–200 nucleotides in size and do not contain expressed open reading frames (ORFs). In Escheric ...

RNA cleavage is a catalytic reaction which defines many types of RNA processing events, including those of metabolite-sensing riboswitch, self-splicing introns, mRNA splicing, tRNA processing, polyA-cleavage, and various small ribozymes such as hairpin and hammerhead ribozy ...

Synthetic riboswitches constructed from RNA aptamers provide a means to control bacterial gene expression using exogenous ligands. A common theme among riboswitches that function at the translational level is that the RNA aptamer interacts with the ribosome-binding site (RBS) of a g ...

Riboswitches modulate gene expression in eubacteria and eukaryotes in response to changing concentrations of small molecule metabolites. In most examples studied to date, riboswitches achieve both metabolite sensing and gene control functions without the obligate involve ...

One of the most versatile riboswitch classes refers to purine nucleoside metabolism. In the cell, purine riboswitches of the respective mRNAs either act at the transcriptional or translational level and off- or on-regulate genes upon binding to their dedicated ligands. Biophysical st ...

Riboswitches are recently discovered messenger RNA motifs involved in gene regulation. They modulate gene expression at various levels, such as transcription, translation, splicing, and mRNA degradation. Because riboswitches exhibit relatively complex structures, they ...