Caenorhabditis elegans glp-4 encodes a valyl aminoacyl tRNA synthetase

Germline stem cell proliferation is necessary to populate the germline with sufficient numbers of cells for gametogenesis and for signaling the soma to control organismal properties such as aging. The Caenorhabditis elegans gene glp-4 was identified by the temperature-sensitive allele bn2 where mutants raised at the restrictive temperature produce adults that are essentially germ cell deficient, containing only a small number of stem cells arrested in the mitotic cycle but otherwise have a morphologically normal soma. We determined that glp-4 encodes a valyl aminoacyl transfer RNA synthetase (VARS-2) and that the probable null phenotype is early larval lethality. Phenotypic analysis indicates glp-4(bn2ts) is partial loss of function in the soma. Structural modeling suggests that bn2 Gly296Asp results in partial loss of function by a novel mechanism: aspartate 296 in the editing pocket induces inappropriate deacylation of correctly charged Val-tRNA(val). Intragenic suppressor mutations are predicted to displace aspartate 296 so that it is less able to catalyze inappropriate deacylation. Thus glp-4(bn2ts) likely causes reduced protein translation due to decreased levels of Val-tRNA(val). The germline, as a reproductive preservation mechanism during unfavorable conditions, signals the soma for organismal aging, stress and pathogen resistance. glp-4(bn2ts) mutants are widely used to generate germline deficient mutants for organismal studies, under the assumption that the soma is unaffected. As reduced translation has also been demonstrated to alter organismal properties, it is unclear whether changes in aging, stress resistance, etc. observed in glp-4(bn2ts) mutants are the result of germline deficiency or reduced translation

Effect of Intensive Versus Standard Blood Pressure Control on Stroke Subtypes

In the SPRINT (Systolic Blood Pressure Intervention Trial), the number of strokes did not differ significantly by treatment group. However, stroke subtypes have heterogeneous causes that could respond differently to intensive blood pressure control. SPRINT participants (N=9361) were randomized to target systolic blood pressures of \u3c120 mm Hg (intensive treatment) compared with \u3c140 mm Hg (standard treatment). We compared incident hemorrhage, cardiac embolism, large- and small-vessel infarctions across treatment arms. Participants randomized to the intensive arm had mean systolic blood pressures of 121.4 mm Hg in the intensive arm (N=4678) and 136.2 mm Hg in the standard arm (N=4683) at one year. Sixty-nine strokes occurred in the intensive arm and 78 in the standard arm when SPRINT was stopped. The breakdown of stroke subtypes across treatment arms included hemorrhagic (intensive treatment, n=6, standard treatment, n=7) and ischemic stroke subtypes (large artery atherosclerosis: intensive treatment n=11, standard treatment, n=13; cardiac embolism: intensive treatment n=11, standard treatment n=15; small artery occlusion: intensive treatment n=8, standard treatment n=8; other ischemic stroke: intensive treatment n=3, standard treatment n=1). Fewer strokes occurred among participants without prior cardiovascular disease in the intensive (n=43) than the standard arm (n=61), but the difference did not reach predefined statistical significance level of 0.05 (P=0.09). The interaction between baseline cardiovascular risk factor status and treatment arm on stroke risk did not reach significance (P=0.05). Similar numbers of stroke subtypes occurred in the intensive BP control and standard control arms of SPRINT

glp-4 Encodes the Valyl Amino-acyl tRNA Synthetase VARS-2

From the Washington University Senior Honors Thesis Abstracts (WUSHTA), Volume 4, Spring 2012. Published by the Office of Undergraduate Research. Joy Zalis Kiefer, Director of Undergraduate Research / Assistant Dean in the College of Arts & Sciences; E. Holly Tasker, Editor; Kristin Sobotka, Undergraduate Research Coordinator. Mentor: Tim Sched

glp-4 Encodes the Valyl Amino-acyl tRNA Synthetase VARS-2

Mentor: Tim Schedl From the Washington University Undergraduate Research Digest: WUURD, Volume 7, Issue 2, Spring 2012. Published by the Office of Undergraduate Research, Joy Zalis Kiefer Director of Undergraduate Research and Assistant Dean in the College of Arts & Sciences; Kristin Sobotka, Editor

Differential Impacts on Host Transcription by ROP and GRA Effectors from the Intracellular Parasite<i>Toxoplasma gondii</i>

ABSTRACTThe intracellular parasiteToxoplasma gondiiemploys a vast array of effector proteins from the rhoptry and dense granule organelles to modulate host cell biology; these effectors are known as ROPs and GRAs, respectively. To examine the individual impacts of ROPs and GRAs on host gene expression, we developed a robust, novel protocol to enrich for ultra-pure populations of a naturally occurring and reproducible population of host cells called uninfected-injected (U-I) cells, whichToxoplasmainjects with ROPs but subsequently fails to invade. We then performed single cell transcriptomic analysis at 1-3 hours post-infection on U-I cells (as well as on uninfected and infected controls) arising from infection with either wild type parasites or parasites lacking the MYR1 protein, which is required for soluble GRAs to cross the parasitophorous vacuole membrane (PVM) and reach the host cell cytosol. Based on comparisons of infected and U-I cells, the host’s earliest response to infection appears to be driven primarily by the injected ROPs, which appear to induce immune and cellular stress pathways. These ROP-dependent pro-inflammatory signatures appear to be counteracted by at least some of the MYR1-dependent GRAs and may be enhanced by the MYR-independent GRAs, (which are found embedded within the PVM). Finally, signatures detected in uninfected bystander cells from the infected monolayers suggests that MYR1-dependent paracrine effects also counteract inflammatory ROP-dependent processes.IMPORTANCEThis work performs the first transcriptomic analysis of U-I cells, captures the earliest stage of a host cell’s interaction withToxoplasma gondii, and dissects the effects of individual classes of parasite effectors on host cell biology.</jats:sec

Differential Impacts on Host Transcription by ROP and GRA Effectors from the Intracellular Parasite Toxoplasma gondii

This work performs transcriptomic analysis of U-I cells, captures the earliest stage of a host cell’s interaction with Toxoplasma gondii, and dissects the effects of individual classes of parasite effectors on host cell biology.The intracellular parasite Toxoplasma gondii employs a vast array of effector proteins from the rhoptry and dense granule organelles to modulate host cell biology; these effectors are known as ROPs and GRAs, respectively. To examine the individual impacts of ROPs and GRAs on host gene expression, we developed a robust, novel protocol to enrich for ultrapure populations of a naturally occurring and reproducible population of host cells called uninfected-injected (U-I) cells, which Toxoplasma injects with ROPs but subsequently fails to invade. We then performed single-cell transcriptomic analysis at 1 to 3 h postinfection on U-I cells (as well as on uninfected and infected controls) arising from infection with either wild-type parasites or parasites lacking the MYR1 protein, which is required for soluble GRAs to cross the parasitophorous vacuole membrane (PVM) and reach the host cell cytosol. Based on comparisons of infected and U-I cells, the host’s earliest response to infection appears to be driven primarily by the injected ROPs, which appear to induce immune and cellular stress pathways. These ROP-dependent proinflammatory signatures appear to be counteracted by at least some of the MYR1-dependent GRAs and may be enhanced by the MYR-independent GRAs (which are found embedded within the PVM). Finally, signatures detected in uninfected bystander cells from the infected monolayers suggest that MYR1-dependent paracrine effects also counteract inflammatory ROP-dependent processes

Differential Impacts on Host Transcription by ROP and GRA Effectors from the Intracellular Parasite Toxoplasma gondii

This work performs transcriptomic analysis of U-I cells, captures the earliest stage of a host cell’s interaction with Toxoplasma gondii , and dissects the effects of individual classes of parasite effectors on host cell biology. </jats:p