25,978 research outputs found
A mutate-and-map protocol for inferring base pairs in structured RNA
Chemical mapping is a widespread technique for structural analysis of nucleic
acids in which a molecule's reactivity to different probes is quantified at
single-nucleotide resolution and used to constrain structural modeling. This
experimental framework has been extensively revisited in the past decade with
new strategies for high-throughput read-outs, chemical modification, and rapid
data analysis. Recently, we have coupled the technique to high-throughput
mutagenesis. Point mutations of a base-paired nucleotide can lead to exposure
of not only that nucleotide but also its interaction partner. Carrying out the
mutation and mapping for the entire system gives an experimental approximation
of the molecules contact map. Here, we give our in-house protocol for this
mutate-and-map strategy, based on 96-well capillary electrophoresis, and we
provide practical tips on interpreting the data to infer nucleic acid
structure.Comment: 22 pages, 5 figure
HiTRACE-Web: an online tool for robust analysis of high-throughput capillary electrophoresis
To facilitate the analysis of large-scale high-throughput capillary
electrophoresis data, we previously proposed a suite of efficient analysis
software named HiTRACE (High Throughput Robust Analysis of Capillary
Electrophoresis). HiTRACE has been used extensively for quantitating data from
RNA and DNA structure mapping experiments, including mutate-and-map contact
inference, chromatin footprinting, the EteRNA RNA design project and other
high-throughput applications. However, HiTRACE is based on a suite of
command-line MATLAB scripts that requires nontrivial efforts to learn, use, and
extend. Here we present HiTRACE-Web, an online version of HiTRACE that includes
standard features previously available in the command-line version as well as
additional features such as automated band annotation and flexible adjustment
of annotations, all via a user-friendly environment. By making use of
parallelization, the on-line workflow is also faster than software
implementations available to most users on their local computers. Free access:
http://hitrace.or
SMT-Based Bounded Model Checking of Fixed-Point Digital Controllers
Digital controllers have several advantages with respect to their flexibility
and design's simplicity. However, they are subject to problems that are not
faced by analog controllers. In particular, these problems are related to the
finite word-length implementation that might lead to overflows, limit cycles,
and time constraints in fixed-point processors. This paper proposes a new
method to detect design's errors in digital controllers using a state-of-the
art bounded model checker based on satisfiability modulo theories. The
experiments with digital controllers for a ball and beam plant demonstrate that
the proposed method can be very effective in finding errors in digital
controllers than other existing approaches based on traditional simulations
tools
Neuropeptide VF neurons promote sleep via the serotonergic raphe
Although several sleep-regulating neuronal populations have been identified, little is known about how they interact with each other to control sleep/wake states. We previously identified neuropeptide VF (NPVF) and the hypothalamic neurons that produce it as a sleep-promoting system (Lee et al., 2017). Here we show using zebrafish that npvf-expressing neurons control sleep via the serotonergic raphe nuclei (RN), a hindbrain structure that is critical for sleep in both diurnal zebrafish and nocturnal mice. Using genetic labeling and calcium imaging, we show that npvf-expressing neurons innervate and can activate serotonergic RN neurons. We also demonstrate that chemogenetic or optogenetic stimulation of npvf-expressing neurons induces sleep in a manner that requires NPVF and serotonin in the RN. Finally, we provide genetic evidence that NPVF acts upstream of serotonin in the RN to maintain normal sleep levels. These findings reveal a novel hypothalamic-hindbrain neuronal circuit for sleep/wake control
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