The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.
Abstract The cerebral cortex is formed by diverse neurons generated sequentially from neural stem cells (NSCs). A clock mechanism has been suggested to underlie the temporal progression of NSCs, which is mainly defined by the transcriptome and the epigenetic state. However, what drives such a developmental clock remains elusive. We show that translational control of histone H3 trimethylation in Lys27 (H3K27me3) modifiers is part of this clock. We find that depletion of Fbl , an rRNA methyltransferase, reduces translation of both Ezh2 methyltransferase and Kdm6b demethylase of H3K27me3 and delays the progression of the NSC state. These defects are partially phenocopied by simultaneous inhibition of H3K27me3 methyltransferase and demethylase, indicating the role of Fbl in the genome-wide H3K27me3 pattern. Therefore, we propose that Fbl drives the intrinsic clock through the translational enhancement of the H3K27me3 modifiers that predominantly define the NSC state.
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Abstract In addition to the cytoplasmic translation system, eukaryotic cells house additional protein synthesis machinery in mitochondria. The importance of this in organello translation is exemplified by clinical pathologies associated with mutations in mitochondrial translation factors. Although a detailed understanding of mitochondrial translation has long been awaited, quantitative, comprehensive and spatiotemporal measurements have posed analytic challenges. The recent development of novel approaches for studying mitochondrial protein synthesis has overcome these issues and expands our understanding of the unique translation system. Here, we review the current technologies for the investigation of mitochondrial translation and the insights provided by their application.
The morphological relationship between lingual papillae and underlying connective tissue papillae of mouse was studied because it is conceivable that the differentiation of epithelium may be affected by its connective tissue. Tongues of adult male mice were fixed in formol or Karnovsky's fixative. After removal of the epithelium by long-term hydrochloric acid treatment at room temperature, the surface of the connective tissue papillae was observed by scanning electron microscopy. Connective tissue papillae that were fungiform in shape and which were distributed at the anterior part of the tongue showed barnacle-like protrusion after removal of the epithelium. Their surface was covered by numerous long filaments running vertically and there was a round depression on the top of each fungiform papilla that may be found to correspond to a taste bud when the results of light and electron microscopy are compared. Filiform papillae in a narrow sense were closely distributed in the anterior part of the tongue. They had a tapered tip declining posteriorly. Each filiform connective tissue papilla was conical in shape and had a round depression that slightly declined antero-downward, and a long narrow depression ran along the anterior edge of each connective tissue papilla. Large conical papillae which distributed at the anterior margin of the intermolar prominence had shovel-like connective tissue papillae which had a depression at the posterior surface unlike that of the filiform papillae. Branched papillae distributed in the posterior part of the prominence had a depression at the anterior surface. Under the light microscope, numerous keratohyaline granules were seen to be contained only in the posterior epithelial cell line of the large conical papillae distributed in the anterior margin of the prominence, while these granules were found only in the anterior epithelial cell line of both filiform and branched papillae. It became clear that the axes of each connective tissue papilla of large conical papillae distributed radically around a single midpoint. Connective tissue papillae of vallate papillae had a beehive-like shape and in follicate papillae there were several vertical elliptical gaps, seen when the epithelium was peeled from the connective tissue.
Double-stranded RNA induces RNA silencing and is cleaved into 21-24 nt small RNA duplexes by Dicer enzyme. A strand of Dicer-generated small RNA duplex (called the guide strand) is then selected by a thermodynamic mechanism to associate with Argonaute (AGO) protein. This AGO-small RNA complex functions to cleave mRNA, repress translation or modify chromatin structure in a sequence-specific manner. Although a model plant, Arabidopsis thaliana, contains 10 AGO genes, their roles and molecular mechanisms remain obscure. In this study, we analyzed the roles of Arabidopsis AGO2 and AGO5. Interestingly, the 5' nucleotide of small RNAs that associated with AGO2 was mainly adenine (85.7%) and that with AGO5 was mainly cytosine (83.5%). Small RNAs that were abundantly cloned from the AGO2 immunoprecipitation fraction (miR163-LL, which is derived from the Lower Left of mature miR163 in pre-miR163, and miR390) and from the AGO5 immunoprecipitation fraction (miR163-UL, which is derived from the Upper Left of mature miR163 in pre-miR163, and miR390(*)) are derived from the single small RNA duplexes, miR163-LL/miR163-UL and miR390/miR390(*). Each strand of the miR163-LL/miR163-UL duplex is selectively sorted to associate with AGO2 or AGO5 in a 5' nucleotide-dependent manner rather than in a thermodynamic stability-dependent manner. Furthermore, we showed that both AGO2 and AGO5 have the ability to bind cucumber mosaic virus-derived small RNAs. These results clearly indicate that the mechanism selecting the guide strand is different among AGO proteins and that multiple AGO genes are involved in anti-virus defense in plants.
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