Identifying the Substrate Specificities of SENP1 and SENP2 in Recognition of Sumoylated Thymine-DNA Glycosylase

SUMO is an essential post-translational protein modification regulated in part by the activity of a family of SUMO-specific proteases known as SENPs. Mammalian cells express six different SENPs with essential and non-redundant functions. The molecular mechanisms that determine the substrate specificities of individual SENPs and their unique functions, however, remain unknown. Thymine-DNA glycosylase (TDG) is an important enzyme that recognizes and repairs G/U and G/T mismatches in the genome during the initial stages of base excision repair (BER), and this role is critical in genome integrity and also DNA demethylation. TDG is sumoylated in vivo and we are interested in exploring the functional importance and regulation of its modification. We previously found that SENP1 preferentially deconjugates sumoylated TDG in vivo, compared with SENP2, and that specificity is determined by the SENP1 catalytic domain (cSENP1). Here, we have used in vitro studies to further explore this specificity by comparing the activities of the SENP1 and SENP2 catalytic domains using multiple substrates, including AMC, RanGAP1 and TDG. Because TDG contains a SUMO interaction motif (SIM) that affects its modification in vivo, we hypothesized that non-covalent, intramolecular SUMO-SIM interactions impede TDG deconjugation. We also hypothesized that the cSENP1 is more efficient at disrupting the TDG SIM-SUMO interaction, thus explaining specificity. To test these hypotheses, we measured deconjugation rates of cSENP1 and cSENP2 over time for SUMO-modified RanGAP1, wild type and SIM mutant TDG. Our result supported a role for SIM binding in impeding deconjugation, and also revealed interesting and unique substrate specificities for both cSENP1 and cSENP2

Targeted mutagenesis in mouse cells and embryos using an enhanced prime editor

Prime editors, novel genome-editing tools consisting of a CRISPR-Cas9 nickase and an engineered reverse transcriptase, can induce targeted mutagenesis. Nevertheless, much effort is required to optimize and improve the efficiency of prime-editing. Herein, we introduce two strategies to improve the editing efficiency using proximal dead sgRNA and chromatin-modulating peptides. We used enhanced prime-editing to generate Igf2 mutant mice with editing frequencies of up to 47% and observed germline transmission, no off-target effects, and a dwarf phenotype. This improved prime-editing method can be efficiently applied to cell research and to generate mouse models.This study was supported by the Chung Yang, Cha Young Sun, & Jang Hi Joo Memorial Fund. This study was also supported by the Bio & Medical Technology Development Program of the National Research Foundation (NRF) of Korea (Korea Mouse Phenotyping Project, NRF-2013M3A9D5072550, NRF-2020M3A9D5A01082439, NRF2019R1A2C2087198, and NRF- 2019M3A9H1103792)

The mu problem and sneutrino inflation

We consider sneutrino inflation and post-inflation cosmology in the singlet extension of the MSSM with approximate Peccei-Quinn(PQ) symmetry, assuming that supersymmetry breaking is mediated by gauge interaction. The PQ symmetry is broken by the intermediate-scale VEVs of two flaton fields, which are determined by the interplay between radiative flaton soft masses and higher order terms. Then, from the flaton VEVs, we obtain the correct mu term and the right-handed(RH) neutrino masses for see-saw mechanism. We show that the RH sneutrino with non-minimal gravity coupling drives inflation, thanks to the same flaton coupling giving rise to the RH neutrino mass. After inflation, extra vector-like states, that are responsible for the radiative breaking of the PQ symmetry, results in thermal inflation with the flaton field, solving the gravitino problem caused by high reheating temperature. Our model predicts the spectral index to be n_s\simeq 0.96 due to the additional efoldings from thermal inflation. We show that a right dark matter abundance comes from the gravitino of 100 keV mass and a successful baryogenesis is possible via Affleck-Dine leptogenesis.Comment: 27 pages, no figures, To appear in JHE

Prevalence of Knee Pain and Its Influence on Quality of Life and Physical Function in the Korean Elderly Population: A Community Based Cross-Sectional Study

To investigate the prevalence of knee pain and its influence on physical function and quality of life (QOL), we examined 504 community residents of Chuncheon, aged ≥ 50 yr. Demographic information was obtained by questionnaire, and radiographic evaluations consisted of weight-bearing semi-flexed knee anteroposterior radiographs. Self-reported QOL and function were assessed using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index and Short Form 12 (SF-12). Performance-based lower extremity function was assessed using the tests consisting of standing balance, usual walk and chair stands. The prevalence of knee pain was 46.2% (32.2% in men and 58.0% in women) and increased with age in women. After adjustment of confounders including the presence of knee OA, the subjects with knee pain had significantly worse WOMAC function and SF-12 scores compared to subjects without knee pain. Among the subjects with knee pain, women had worse WOMAC and SF-12 scores than men. Subjects with knee pain had worse physical performance score compared to those without knee pain, especially among females. In conclusion, the prevalence of knee pain is high (32.2% in men and 58.0% in women) in this elderly community population in Korea. Independent of knee OA and other confounding factors, subjects with knee pain have more than 5-fold increase in the risk of belonging to the worst lower extremity function compared to subjects without knee pain

Effect of Surface Structure Complexity on Interfacial Droplet Behavior of Superhydrophobic Titanium Surfaces for Robust Dropwise Condensation

In general, the dropwise condensation supported by superhydrophobic surfaces results in enhanced heat transfer relative to condensation on normal surfaces. However, in supersaturated environments that exceed a certain supersaturation threshold, moisture penetrates the surface structures and results in attached condensation, which reduces the condensation heat transfer efficiency. Therefore, when designing superhydrophobic surfaces for condensers, the surface structure must be resistant to attached condensation in supersaturated conditions. The gap size and complexity of the micro/nanoscale surface structure are the main factors that can be controlled to maintain water repellency in supersaturated environments. In this study, the condensation heat exchange performance was characterized for three different superhydrophobic titanium surface structures via droplet behavior (DB) mapping to evaluate their suitability for power plant condensers. In addition, it was demonstrated that increasing the surface structure complexity increases the versatility of the titanium surfaces by extending the window for improved heat exchange performance. This study demonstrates the usefulness of DB mapping for evaluating the performance of superhydrophobic surfaces regarding their applicability for industrial condenser systems.11Nsciescopu

Complementary Regulation of BfmRS Two-Component and AbaIR Quorum Sensing Systems to Express Virulence-Associated Genes in Acinetobacter baumannii

Acinetobacter baumannii expresses various virulence factors to adapt to hostile environments and infect susceptible hosts. This study investigated the regulatory network of the BfmRS two-component and AbaIR quorum sensing (QS) systems in the expression of virulence-associated genes in A. baumannii ATCC 17978. The ΔbfmS mutant exhibited a significant decrease in surface motility, which presumably resulted from the low expression of pilT and A1S_0112-A1S_0119 gene cluster. The ΔbfmR mutant displayed a significant reduction in biofilm and pellicle formation due to the low expression of csu operon. The deletion of abaR did not affect the expression of bfmR or bfmS. However, the expression of abaR and abaI was upregulated in the ΔbfmR mutant. The ΔbfmR mutant also produced more autoinducers than did the wild-type strain, suggesting that BfmR negatively regulates the AbaIR QS system. The ΔbfmS mutant exhibited no autoinducer production in the bioassay system. The expression of the A1S_0112-A1S_0119 gene cluster was downregulated in the ΔabaR mutant, whereas the expression of csu operon was upregulated in this mutant with a high cell density. In conclusion, for the first time, we demonstrated that the BfmRS-AbaIR QS system axis regulated the expression of virulence-associated genes in A. baumannii. This study provides new insights into the complex network system involved in the regulation of virulence-associated genes underlying the pathogenicity of A. baumannii

Alteration of gut microbiota by vancomycin and bacitracin improves insulin resistance via glucagon-like peptide 1 in diet-induced obesity

Firmicutes and Bacteroidetes, 2 major phyla of gut microbiota, are involved in lipid and bile acid metabolism to maintain systemic energy homeostasis in host. Recently, accumulating evidence has suggested that dietary changes promptly induce the alteration of abundance of both Firmicutes and Bacteroidetes in obesity and its related metabolic diseases. Nevertheless, the metabolic roles of Firmicutes and Bacteroidetes on such disease states remain unclear. The aim of this study was to determine the effects of antibiotic-induced depletion of Firmicutes and Bacteroidetes on dysregulation of energy homeostasis in obesity. Treatment of C57BL/6J mice with the antibiotics (vancomycin [V] and bacitracin [B]), in the drinking water, before diet-induced obesity (DIO) greatly decreased both Firmicutes and Bacteroidetes in the gut as revealed by pyrosequencing of the microbial 16S rRNA gene. Concomitantly, systemic glucose intolerance, hyperinsulinemia, and insulin resistance in DIO were ameliorated via augmentation of GLP-1 secretion (active form; 2.03-fold, total form; 5.09-fold) independently of obesity as compared with untreated DIO controls. Furthermore, there were increases in metabolically beneficial metabolites derived from the gut. Together, our data suggest that Firmicutes and Bacteroidetes potentially mediate insulin resistance through modulation of GLP-1 secretion in obesity.—Hwang, I., Park, Y. J., Kim, Y. -R., Kim, Y.N.,Ka, S., Lee,H.Y., Seong, J.K., Seok,Y. -J., andKim, J.B. Alteration of gut microbiota by vancomycin and bacitracin improves insulin resistance via glucagon-like peptide 1 in diet-induced obesity.OAIID:oai:osos.snu.ac.kr:snu2015-01/102/0000005231/3ADJUST_YN:YEMP_ID:A072580DEPT_CD:3344CITE_RATE:5.043FILENAME:cv no.111.pdfDEPT_NM:생명과학부SCOPUS_YN:YCONFIRM: