264 research outputs found
Random Moment Problems under Constraints
We investigate moment sequences of probability measures on
under constraints of certain moments being fixed. This
corresponds to studying sections of -th moment spaces, i.e. the spaces of
moment sequences of order . By equipping these sections with the uniform or
more general probability distributions, we manage to give for large precise
results on the (probabilistic) barycenters of moment space sections and the
fluctuations of random moments around these barycenters. The measures
associated to the barycenters belong to the Bernstein-Szeg\H{o} class and show
strong universal behavior. We prove Gaussian fluctuations and moderate and
large deviations principles. Furthermore, we demonstrate how fixing moments by
a constraint leads to breaking the connection between random moments and random
matrices.Comment: 43 page
Cytoplasmic RNA decay pathways - enzymes and mechanisms
RNA decay plays a crucial role in post-transcriptional regulation of gene expression. Work conducted over the last decades has defined the major mRNA decay pathways, as well as enzymes and their cofactors responsible for these processes. In contrast, our knowledge of the mechanisms of degradation of non-protein coding RNA species is more fragmentary. This review is focused on the cytoplasmic pathways of mRNA and ncRNA degradation in eukaryotes. The major 3’ to 5’ and 5’ to 3’ mRNA decay pathways are described with emphasis on the mechanisms of their activation by the deprotection of RNA ends. More recently discovered 3’-end modifications such as uridylation, and their relevance to cytoplasmic mRNA decay in various model organisms, are also discussed. Finally, we provide up-to-date findings concerning various pathways of non-coding RNA decay in the cytoplasm
Retoryczne znaczenie liczb palindromicznych w Biblii
Obrazowość liczb palindromicznych w Biblii służyć może za klasyczną perorę, jako dosadna eksplikacja w postaci dosłownie przytoczonych liczebników. Ale zapis liczbowy to rzadki i szczególny przypadek. Częściej chodzi o strukturalny „kod” w rozkładzie geometrycznym, organizujący wypowiedź retoryczną i umożliwiający funkcjonowanie jej na obszarze różnych języków
Perlman syndrome nuclease DIS3L2 controls cytoplasmic non-coding RNAs and provides surveillance pathway for maturing snRNAs
The exosome-independent exoribonuclease DIS3L2
is mutated in Perlman syndrome. Here, we used extensive
global transcriptomic and targeted biochemical
analyses to identify novel DIS3L2 substrates in
human cells. We show that DIS3L2 regulates pol
II transcripts, comprising selected canonical and
histone-coding mRNAs, and a novel FTL short RNA
from the ferritin mRNA 5� UTR. Importantly, DIS3L2
contributes to surveillance of maturing snRNAs during
their cytoplasmic processing. Among pol III transcripts,
DIS3L2 particularly targets vault and Y RNAs
and an Alu-like element BC200 RNA, but not Alu repeats,
which are removed by exosome-associated
DIS3. Using 3� RACE-Seq, we demonstrate that
all novel DIS3L2 substrates are uridylated in vivo
by TUT4/TUT7 poly(U) polymerases. Uridylationdependent
DIS3L2-mediated decay can be recapitulated
in vitro, thus reinforcing the tight cooperation
between DIS3L2 and TUTases. Together these results
indicate that catalytically inactive DIS3L2, characteristic
of Perlman syndrome, can lead to deregulation
of its target RNAs to disturb transcriptome homeostasis
A short splicing isoform of HBS1L links the cytoplasmic exosome and SKI complexes in humans.
The exosome complex is a major eukaryotic exoribonuclease that requires the SKI complex for its activity in the cytoplasm. In yeast, the Ski7 protein links both complexes, whereas a functional equivalent of the Ski7 has remained unknown in the human genome.Proteomic analysis revealed that a previously uncharacterized short splicing isoform of HBS1L (HBS1LV3) is the long-sought factor linking the exosome and SKI complexes in humans. In contrast, the canonical HBS1L variant, HBS1LV1, which acts as a ribosome dissociation factor, does not associate with the exosome and instead interacts with the mRNA surveillance factor PELOTA. Interestingly, both HBS1LV1 and HBS1LV3 interact with the SKI complex and HBS1LV1 seems to antagonize SKI/exosome supercomplex formation. HBS1LV3 contains a unique C-terminal region of unknown structure, with a conserved RxxxFxxxL motif responsible for exosome binding and may interact with the exosome core subunit RRP43 in a way that resembles the association between Rrp6 RNase and Rrp43 in yeast. HBS1LV3 or the SKI complex helicase (SKI2W) depletion similarly affected the transcriptome, deregulating multiple genes. Furthermore, half-lives of representative upregulated mRNAs were increased, supporting the involvement of HBS1LV3 and SKI2W in the same mRNA degradation pathway, essential for transcriptome homeostasis in the cytoplasm
Rekomendacje diagnostyczno-terapeutyczne w zespole jelita nadwrażliwego
Niniejsze rekomendacje diagnostyczno-terapeutyczne
w zespole jelita nadwrażliwego zostały przygotowane
przez specjalną grupę roboczą powołaną przez
Zarząd Główny Polskiego Towarzystwa Gastroenterologii. Omówiono definicję i kryteria rozpoznania,
obraz kliniczny i klasyfikację zespołu oraz podano
zalecenia dotyczące jego leczenia.
Gastroenterologia Kliniczna 2009, tom 1, nr 1, 9-1
A precision RNA degradation machinery shapes stem cell development
In this issue, Belair et al. (2019. J. Cell Biol. https://doi.org/10.1083/jcb.201811148) show that, together with a complex network of transcription factors and chromatin modifiers, the RNA exosome regulates embryonic stem cell (ESC) differentiation and pluripotency.publishe
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