Clearance of germ granules in the soma

Germ granules are ribonucleoprotein complexes specifically segregated into germ cell lineages in diverse organisms. Recent studies indicate that multiple mechanisms are involved in the clearance of germ granules and their components in somatic cells in Caenorhabditis elegans embryos

The nucleoporin Nup205/NPP-3 is lost near centrosomes at mitotic onset and can modulate the timing of this process in Caenorhabditis elegans embryos

This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License.Regulation of mitosis in time and space is critical for proper cell division. We conducted an RNA interference–based modifier screen to identify novel regulators of mitosis in Caenorhabditis elegans embryos. Of particular interest, this screen revealed that the Nup205 nucleoporin NPP-3 can negatively modulate the timing of mitotic onset. Furthermore, we discovered that NPP-3 and nucleoporins that are associated with it are lost from the nuclear envelope (NE) in the vicinity of centrosomes at the onset of mitosis. We demonstrate that centrosomes are both necessary and sufficient for NPP-3 local loss, which also requires the activity of the Aurora-A kinase AIR-1. Our findings taken together support a model in which centrosomes and AIR-1 promote timely onset of mitosis by locally removing NPP-3 and associated nucleoporins from the NE.V.H. was supported by a Roche postdoctoral fellowship (Mkl/stm 120-2007) and by an MHV postdoctoral fellowship from the Swiss National Science Foundation (PMPD33-118694). Additional support was provided by the Swiss Cancer League (grant KLS 2160-02-2008 to P.G.). Work in the laboratory of P.A. was funded by the Spanish Ministry of Science and Innovation (BFU2010-15478).Peer reviewe

Caenorhabditis elegans ortholog of the p24/p22 subunit, DNC-3, is essential for the formation of the dynactin complex by bridging DNC-1/p150Glued and DNC-2/dynamitin

Dynactin is a multisubunit protein complex required for the activity of cytoplasmic dynein. In Caenorhabditis elegans, although 10 of the 11 dynactin subunits were identified based on the sequence similarities to their orthologs, the p24/p22 subunit has not been detected in the genome. Here, we demonstrate that DNC-3 (W10G11.20) is the functional counterpart of the p24/p22 subunit in C. elegans. RNAi phenotypes and subcellular localization of DNC-3 in early C. elegans embryos were nearly identical to those of the known dynactin components. All other dynactin subunits were co-immunoprecipitated with DNC-3, indicating that DNC-3 is a core component of dynactin. Furthermore, the overall secondary structure of DNC-3 resembles to those of the mammalian and yeast p24/p22. We found that DNC-3 is required for the localization of the DNC-1/p150Glued and DNC-2/dynamitin, the two components of the projection arm of dynactin, to the nuclear envelope of meiotic nuclei in the adult gonad. Moreover, DNC-3 physically interacted with DNC-1 and DNC-2 and significantly enhanced the binding ability between DNC-1 and DNC-2 in vitro. These results suggest that DNC-3 is essential for the formation of the projection arm subcomplex of dynactin

Investigation of enhanced intracellular delivery of nanomaterials modified with novel cell-penetrating zwitterionic peptide-lipid derivatives

Functionalized drug delivery systems have been investigated to improve the targetability and intracellular translocation of therapeutic drugs. We developed high functionality and quality lipids that met unique requirements, focusing on the quality of functional lipids for the preparation of targeted nanoparticles using microfluidic devices. While searching for a lipid with high solubility and dispersibility in solvents, which is one of the requirements, we noted that KK-(EK)4-lipid imparts nonspecific cellular association to polyethylene glycol (PEG)-modified (PEGylated) liposomes, such as cell-penetrating peptides (CPPs). We investigated whether KK-(EK)4-lipid, which has a near-neutral charge, is a novel CPP-modified lipid that enhances the intracellular translocation of nanoparticles. However, the cellular association mechanism of KK-(EK)4-lipid is unknown. Therefore, we synthesized (EK)n-lipid derivatives based on the sequence of KK-(EK)4-lipid and determined the sequence sites involved in cellular association. In addition, KK-(EK)4-lipid was applied to extracellular vesicles (EVs) and mRNA encapsulated lipid nanoparticles (mRNA-LNPs). KK-(EK)4-lipid-modified EVs and mRNA-LNPs showed higher cellular association and in vitro protein expression, respectively, compared to unmodified ones. We elucidated KK-(EK)4-lipid to have potential for applicability in the intracellular delivery of liposomes, EVs, and mRNA-LNPs

A Tracking Method for 2D canvas in MR-based interactive painting system

Abstract-We have proposed a mixed reality based painting system. In this paper, we tackle a problem in our previous painting system that fully relies on magnetic sensor that is attached on the canvas; the users needed to detach and attach a sensor on the canvas during painting when they want to switch the canvas. Instead of that, in this paper, we aim to automatically detect the shape of the canvas for registration purpose. Using the shape or region detection method such as MSER (maximally stable extremal regions), we detect and track the shape on the canvas on the captured camera image. We then compute the camera pose for virtually overlay the painting result. Using the brush device, we can draw and paint freely on the tracked canvases. We show that using visual based tracking method, we can generate the equivalent result compared to the result of using the sensor

A Tracking Method for 2D canvas in MR-based interactive painting system

ABSTRACT We have proposed a mixed reality (MR) based painting system. In this paper, we tackle a problem that exists in the conventional method that fully relies on magnetic sensor that is attached on the canvas; the users needed to detach and attach a sensor on the canvas during painting when they want to switch the canvas. Therefore, we aim to automatically detect the shape of the canvas for registration purpose using vision-based tracking method. Using a region detection method such as MSER, we detect and track the shape on the canvas. We then compute the camera pose for virtually overlaying the painting result. Finally, we can generate equivalent results compared to the result of using the sensor

Biology and genome of a newly discovered sibling species of Caenorhabditis elegans

A ‘sibling’ species of the model organism Caenorhabditis elegans has long been sought for use in comparative analyses that would enable deep evolutionary interpretations of biological phenomena. Here, we describe the first sibling species of C. elegans, C. inopinata n. sp., isolated from fig syconia in Okinawa, Japan. We investigate the morphology, developmental processes and behaviour of C. inopinata, which differ significantly from those of C. elegans. The 123-Mb C. inopinata genome was sequenced and assembled into six nuclear chromosomes, allowing delineation of Caenorhabditis genome evolution and revealing unique characteristics, such as highly expanded transposable elements that might have contributed to the genome evolution of C. inopinata. In addition, C. inopinata exhibits massive gene losses in chemoreceptor gene families, which could be correlated with its limited habitat area. We have developed genetic and molecular techniques for C. inopinata; thus C. inopinata provides an exciting new platform for comparative evolutionary studies