No abstract

More than a decade has passed since the discovery of RNA interference (RNAi), an eukaryotic sequence-specific degradation of mRNA induced by complementary double-stranded RNA (dsRNA). RNAi became a common tool for controlled down-regulation of gene expression in cultured cells, as well as in various model organisms. This review summarizes RNAi-based tools for silencing genes in living mammals, which include: (i) transgenic RNAi strategies, where RNAi is triggered by a transgene transmitted through the germline and (ii) approaches, where an RNAi trigger is delivered into an adult animal.

Production of small RNAs by ribonuclease III Dicer is a key step in microRNA and RNA interference pathways, which employ Dicer-produced small RNAs as sequence-specific silencing guides. Further studies and manipulations of microRNA and RNA interference pathways would benefit from identification of small-molecule modulators. Here, we report a study of a fluorescence-based in vitro Dicer cleavage assay, which was adapted for high-throughput screening. The kinetic assay can be performed under single-turnover conditions (35 nM substrate and 70 nM Dicer) in a small volume (5 µL), which makes it suitable for high-throughput screening in a 1536-well format. As a proof of principle, a small library of bioactive compounds was analyzed, demonstrating potential of the assay.

We show that depletion of nuclear Like-Sm 8 (LSm8) dramatically increases processing body (P-body) number, provide the explanation that LSm8 acts via the alteration of the nuclear–cytoplasmic distribution of LSm2–7 proteins, and propose a model that P-bodies form via self-organization.

Unique observation and analysis of gravity wave (GW) propagation in the ionosphere was performed on the basis of multipoint and multifrequency continuous Doppler sounding in the Czech Republic. The sounding radio waves of various frequencies reflect at different heights. Thus, the propagation of GWs can be studied in three‐dimensional space using the time (phase) delays between observation of corresponding signatures at different reflection points that are separated both horizontally and vertically. The individual reflection points correspond to different sounding paths (transmitter‐receiver pairs) and are usually at heights between ~150 and ~260 km, depending on ionospheric conditions. It is shown that the wave vectors of the observed GWs were mostly directed obliquely downward, which means that the energy propagated obliquely upward. It was observed that energy of GWs decreased with height in the upper atmosphere. The observed average attenuation was around 0.14 dB/km.