Search results for "knockdown"
showing 10 items of 178 documents
Evidence for an instructive role of apoptosis during the metamorphosis of Hydractinia echinata (Hydrozoa)
2011
Apoptosis is a highly conserved mechanism of cell deletion that destroys redundant, dysfunctional, damaged, and diseased cells. Furthermore, apoptotic cell death is essential during the development of multicellular organisms. However, there are only a few examples where the occurrence of apoptosis has been shown to be a direct prerequisite for developmental processes. As described previously by our group, the degradation of larval tissue during the first half of the metamorphosis of Hydractinia echinata involves extensive cell death. A large number of cells are removed, and we observed several cellular features of apoptotic cell death in the dying tissue, e.g., nucleosomal DNA fragmentation…
Morpholino knockdown of the ubiquitously expressed transmembrane serine protease TMPRSS4a in zebrafish embryos exhibits severe defects in organogenes…
2011
AbstractOver the past years the members of the type II transmembrane serine protease (TTSP) family have emerged as new players in mammalian biology. TMPRSS4 (transmembraneprotease/serine) is overexpressed in several human cancer tissues, promoting invasion, migration, and metastasis. However, the physiological function has not yet been elucidated. Here, we present morpholino knockdown studies targeting TMPRSS4a, a homolog of human TMPRSS4 in zebrafish embryos. By RT-PCR, we could demonstrate an expression of this protease already 5 h post-fertilization, suggesting important functions in the early stages of embryonic development. Indeed,in vivogene silencing caused severe defects in tissue d…
SANS (USH1G) regulates pre-mRNA splicing by mediating the intra-nuclear transfer of tri-snRNP complexes
2021
Abstract Splicing is catalyzed by the spliceosome, a compositionally dynamic complex assembled stepwise on pre-mRNA. We reveal links between splicing machinery components and the intrinsically disordered ciliopathy protein SANS. Pathogenic mutations in SANS/USH1G lead to Usher syndrome—the most common cause of deaf-blindness. Previously, SANS was shown to function only in the cytosol and primary cilia. Here, we have uncovered molecular links between SANS and pre-mRNA splicing catalyzed by the spliceosome in the nucleus. We show that SANS is found in Cajal bodies and nuclear speckles, where it interacts with components of spliceosomal sub-complexes such as SF3B1 and the large splicing cofact…
Syntaxin13 expression is regulated by mammalian target of rapamycin (mTOR) in injured neurons to promote axon regeneration.
2014
Injured peripheral neurons successfully activate intrinsic signaling pathways to enable axon regeneration. We have previously shown that dorsal root ganglia (DRG) neurons activate the mammalian target of rapamycin (mTOR) pathway following injury and that this activity enhances their axon growth capacity. mTOR plays a critical role in protein synthesis, but the mTOR-dependent proteins enhancing the regenerative capacity of DRG neurons remain unknown. To identify proteins whose expression is regulated by injury in an mTOR-dependent manner, we analyzed the protein composition of DRGs from mice in which we genetically activated mTOR and from mice with or without a prior nerve injury. Quantitati…
The Wnt-specific astacin proteinase HAS-7 restricts head organizer formation in Hydra
2021
Abstract Background The Hydra head organizer acts as a signaling center that initiates and maintains the primary body axis in steady state polyps and during budding or regeneration. Wnt/beta-Catenin signaling functions as a primary cue controlling this process, but how Wnt ligand activity is locally restricted at the protein level is poorly understood. Here we report a proteomic analysis of Hydra head tissue leading to the identification of an astacin family proteinase as a Wnt processing factor. Results Hydra astacin-7 (HAS-7) is expressed from gland cells as an apical-distal gradient in the body column, peaking close beneath the tentacle zone. HAS-7 siRNA knockdown abrogates HyWnt3 proteo…
Dual-targeting siRNAs.
2010
We have developed an algorithm for the prediction of dual-targeting short interfering RNAs (siRNAs) in which both strands are deliberately designed to separately target different mRNA transcripts with complete complementarity. An advantage of this approach versus the use of two separate duplexes is that only two strands, as opposed to four, are competing for entry into the RNA-induced silencing complex. We chose to design our dual-targeting siRNAs as Dicer substrate 25/27mer siRNAs, since design features resembling pre-microRNAs (miRNAs) can be introduced for Dicer processing. Seven different dual-targeting siRNAs targeting genes that are potential targets in cancer therapy have been develo…
Multifunctional Cationic PeptoStars as siRNA Carrier: Influence of Architecture and Histidine Modification on Knockdown Potential.
2019
RNA interference provides enormous potential for the treatment of several diseases, including cancer. Nevertheless, successful therapies based on siRNA require overcoming various challenges, such as poor pharmacokinetic characteristics of the small RNA molecule and inefficient cytosolic accumulation. In this respect, the development of functional siRNA carrier systems is a major task in biomedical research. To provide such a desired system, the synthesis of 3-arm and 6-arm PeptoStars is aimed for. The different branched polypept(o)idic architectures share a stealth-like polysarcosine corona for efficient shielding and a multifunctional polylysine core, which can be independently varied in s…
Tetraspanin CD151 Mediates Papillomavirus Type 16 Endocytosis
2013
ABSTRACT Human papillomavirus type 16 (HPV16) is the primary etiologic agent for cervical cancer. The infectious entry of HPV16 into cells occurs via a so-far poorly characterized clathrin- and caveolin-independent endocytic pathway, which involves tetraspanin proteins and actin. In this study, we investigated the specific role of the tetraspanin CD151 in the early steps of HPV16 infection. We show that surface-bound HPV16 moves together with CD151 within the plane of the membrane before they cointernalize into endosomes. Depletion of endogenous CD151 did not affect binding of viral particles to cells but resulted in reduction of HPV16 endocytosis. HPV16 uptake is dependent on the C-termina…
AP-1 Transcription Factor Serves as a Molecular Switch between Chlamydia pneumoniae Replication and Persistence
2015
ABSTRACT Chlamydia pneumoniae is a Gram-negative bacterium that causes acute or chronic respiratory infections. As obligate intracellular pathogens, chlamydiae efficiently manipulate host cell processes to ensure their intracellular development. Here we focused on the interaction of chlamydiae with the host cell transcription factor activator protein 1 (AP-1) and its consequence on chlamydial development. During Chlamydia pneumoniae infection, the expression and activity of AP-1 family proteins c-Jun, c-Fos, and ATF-2 were regulated in a time- and dose-dependent manner. We observed that the c-Jun protein and its phosphorylation level significantly increased during C. pneumoniae development.…
Enhancing Gene Knockdown Efficiencies by Comparing siRNA-Loaded Cationic Nanogel Particles of Different Sizes
2015
lt;pgt;In order to silence the expression levels of pathogenic genes, small interfering RNA (siRNA) requires a nano-sized carrier for its safe and stable delivery into cells. In this research highlight, we focus on well-defined cationic nanohydrogel particles developed in our group for such purposes. To investigate the nanogels’ mechanism for enhanced knockdown efficiencies, we recently synthesized two sets of particles with similar material composition and siRNA-loading characteristics, but – according to the manufacturing process – of different sizes. Within this study, 100-nm-sized nanogel particles loaded with siRNA accumulated inside the lysosomes already after 4 h and could not induce…