Fgfbp1 is essential for the cellular survival during zebrafish embryogenesis

Fibroblast growth factor binding protein 1 (FGFBP1) is expressed in various tumors and may serve as a diagnostic marker and/or a therapeutic target. Previous studies suggested FGFBP1 functions as an angiogenic switch molecule by regulating the activity of FGF2, and it was later found to associate with a broad spectrum of FGFs. To study FGFBP1, we used zebrafish, in which the function of extracellular matrix protein can be easily studied in intact tissues or organisms. When Fgfbp1 expression was knocked down, morphants manifested massive cell death and structural abnormalities. Cell death was most prominent in the brain and the neural tube, but not limited to those regions. These findings suggest that the primary function of Fgfbp1 may be to sustain cellular survival throughout embryogenesis. For comparison, the expression of fgf2 was limited to the early stage of embryogenesis and fgf2 morphants showed more severe phenotype, with high morbidity before reaching 14-somites. Taken together, our work reveals the physiologic function of Fgfbp1, and that its function could be exerted in a Fgf2-independent manner.     

Association of myostatin deficiency with collagen related disease-umbilical hernia and tippy toe standing in pigs

Transgenic Research - Herein, we investigate the high incidence of umbilical hernia and tippy-toe standing and their underlying changes in gene expression and proliferation in myostatin knockout...     

Hydroxychloroquine-mediated inhibition of SARS-CoV-2 entry is attenuated by TMPRSS2

Hydroxychloroquine, used to treat malaria and some autoimmune disorders, potently inhibits viral infection of SARS coronavirus (SARS-CoV-1) and SARS-CoV-2 in cell-culture studies. However, human clinical trials of hydroxychloroquine failed to establish its usefulness as treatment for COVID-19. This compound is known to interfere with endosomal acidification necessary to the proteolytic activity of cathepsins. Following receptor binding and endocytosis, cathepsin L can cleave the SARS-CoV-1 and SARS-CoV-2 spike (S) proteins, thereby activating membrane fusion for cell entry. The plasma membrane-associated protease TMPRSS2 can similarly cleave these S proteins and activate viral entry at the cell surface. Here we show that the SARS-CoV-2 entry process is more dependent than that of SARS-CoV-1 on TMPRSS2 expression. This difference can be reversed when the furin-cleavage site of the SARS-CoV-2 S protein is ablated or when it is introduced into the SARS-CoV-1 S protein. We also show that hydroxychloroquine efficiently blocks viral entry mediated by cathepsin L, but not by TMPRSS2, and that a combination of hydroxychloroquine and a clinically-tested TMPRSS2 inhibitor prevents SARS-CoV-2 infection more potently than either drug alone. These studies identify functional differences between SARS-CoV-1 and -2 entry processes, and provide a mechanistic explanation for the limited in vivo utility of hydroxychloroquine as a treatment for COVID-19.     

Regulation of ICAM‐1 expression in gingival fibroblasts infected with high‐glucose‐treated P. gingivalis

Porphyromonas gingivalis is a major pathogen in the initiation and progression of periodontal disease, which is recognized as a common complication of diabetes. ICAM‐1 expression by human gingival fibroblasts (HGFs) is crucial for regulating local inflammatory responses in inflamed periodontal tissues. However, the effect of P. gingivalis in a high‐glucose situation in regulating HGF function is not understood. The P. gingivalis strain CCUG25226 was used to study the mechanisms underlying the modulation of HGF ICAM‐1 expression by invasion of high‐glucose‐treated P. gingivalis (HGPg). A high‐glucose condition upregulated fimA mRNA expression in P. gingivalis and increased its invasion ability in HGFs. HGF invasion with HGPg induced increases in the expression of ICAM‐1. By using specific inhibitors and short hairpin RNA (shRNA), we have demonstrated that the activation of p38 MAPK and Akt pathways is critical for HGPg‐induced ICAM‐1 expression. Luciferase reporters and chromatin immunoprecipitation assays suggest that HGPg invasion increases NF‐κB‐ and Sp1‐DNA‐binding activities in HGFs. Inhibition of NF‐κB and Sp1 activations blocked the HGPg‐induced ICAM‐1 promoter activity and expression. The effect of HGPg on HGF signalling and ICAM‐1 expression is mediated by CXC chemokine receptor 4 (CXCR4). Our findings identify the molecular pathways underlying HGPg‐dependent ICAM‐1 expression in HGFs, providing insight into the effect of P. gingivalis invasion in HGFs.     

Impacts of Intergroup Interactions on Intragroup Behavioral Changes in Javan Gibbons (Hylobates moloch)

International Journal of Primatology - Agonistic intergroup interactions can cause individual costs such as physical injuries, increased physiological stress, and disrupted intragroup social...     

Arabidopsis Brassinosteroid-overproducing gulliver3-D/dwarf4-D mutants exhibit altered responses to Jasmonic acid and pathogen

Key message

Arabidopsis gulliver3 - D/dwarf4 - D displays growth-promoting phenotypes due to activation tagging of a key brassinosteroid biosynthetic gene DWARF4. In gul3-D/dwf4-D , the Jasmonate and Salicylate signaling pathways were relatively activated and suppressed, respectively.

Abstract

Energy allocation between growth and defense is elegantly balanced to achieve optimal development in plants. Brassinosteroids (BRs), steroidal hormones essential for plant growth, are regulated by other plant hormones, including auxin and jasmonates (JA); auxin stimulates the expression of a key brassinosteroid (BR) biosynthetic gene, DWARF4 (DWF4), whereas JA represses it. To better understand the interaction mechanisms between growth and defense, we isolated a fast-growing mutant, gulliver3-D (gul3-D), that resulted from the activation tagging of DWF4, and examined the response of this mutant to defense signals, including JA, Pseudomonas syringae pv. tomato (Pst DC3000) infection, and wounding. The degree of root growth inhibition following MeJA treatment was significantly decreased in gul3-1D/dwf4-5D relative to the wild type, suggesting that JA signaling is partially desensitized in gul3-1D. Quantitative RT-PCR analysis of the genes involved in JA and salicylic acid (SA) responses, including MYC2, PDF1.2, CORI3, PR1, and PR2, revealed that JA signaling was preferentially activated in gul3-1D, whereas SA signaling was suppressed. As a result, gul3-1D was more susceptible to a biotrophic pathogen, Pst DC3000. Based on our results, we propose a model in which BR and JA cooperate to balance energy allocation between growth and defense responses. In ambient conditions, BRs promote plant growth; however, when stresses trigger JA signaling, JA compromises BR signaling by downregulating DWF4 expression.     

ATM-deficient human fibroblast cells are resistant to low levels of DNA double-strand break induced apoptosis and subsequently undergo drug-induced premature senescence

DNA DSBs are induced by IR or radiomimetic drugs such as doxorubicin. It has been indicated that cells from ataxia-telangiectasia patients are highly sensitive to radiation due to defects in DNA repair, but whether they have impairment in apoptosis has not been fully elucidated. A-T cells showed increased sensitivity to high levels of DNA damage, however, they were more resistant to low doses. Normal cells treated with combination of KU55933, a specific ATM kinase inhibitor, and doxorubicin showed increased resistance as they do in a similar manner to A-T cells. A-T cells have higher viability but more DNA breaks, in addition, the activations of p53 and apoptotic proteins (Bax and caspase-3) were deficient, but Akt expression was enhanced. A-T cells subsequently underwent premature senescence after treatment with a low dose of doxorubicin, which was confirmed by G2 accumulation, senescent morphology, and SA-β-gal positive until 15 days repair incubation. Finally, A-T cells are radio-resistant at low doses due to its defectiveness in detecting DNA damage and apoptosis, but the accumulation of DNA damage leads cells to premature senescence.     

Highly tolerated amino acid substitutions increase the fidelity of Escherichia coli DNA polymerase I

Fidelity of DNA synthesis, catalyzed by DNA polymerases, is critical for the maintenance of the integrity of the genome. Mutant polymerases with elevated accuracy (antimutators) have been observed, but these mainly involve increased exonuclease proofreading or large decreases in polymerase activity. We have determined the tolerance of DNA polymerase for amino acid substitutions in the active site and in different segments of E. coli DNA polymerase I and have determined the effects of these substitutions on the fidelity of DNA synthesis. We established a DNA polymerase I mutant library, with random substitutions throughout the polymerase domain. This random library was first selected for activity. The essentiality of DNA polymerases and their sequence and structural conservation suggests that few amino acid substitutions would be tolerated. However, we report that two-thirds of single base substitutions were tolerated without loss of activity, and plasticity often occurs at evolutionarily conserved regions. We screened 408 members of the active library for alterations in fidelity of DNA synthesis in Escherichia coli expressing the mutant polymerases and carrying a second plasmid containing a beta-lactamase reporter. Mutation frequencies varied from 1/1000- to 1000-fold greater compared with wild type. Mutations that produced an antimutator phenotype were distributed throughout the polymerase domain, with 12% clustered in the M-helix. We confirmed that a single mutation in this segment results in increased base discrimination. Thus, this work identifies the M-helix as a determinant of fidelity and suggests that polymerases can tolerate many substitutions that alter fidelity without incurring major changes in activity.     

Morphological and Molecular Characterization of Philometroides seriolae from Japanese Amberjack Seriola quinqueradiata caught in East Sea,Republic of Korea

The Japanese amberjack Seriolae quinqueradiata is one of the most consumed fish species among the Koreans. However, information regarding parasitic infection in Japanese amberjack is scarce. This study described the morphological and molecular characteristics of a species of philometrid nematode, Philometroides seriolae, which was recovered from Japanese amberjack. This fish was caught in the sea of Goseong-gun, Gangwon-do, Republic of Korea (Korea). Six P. seriolae (Nematoda: Philometridae) were recovered from 2 Japanese amberjacks. These parasites were subgravid female which were 325–420 mm long and 2.95–3.27 mm wide. Furthermore, they had typical papillae distributed on their body surface with 14 papillae at the apical view. Sequence analysis of the small subunits of ribosomal RNA (SSU rRNA) showed high sequence identity (99.8%, 1,607/1,611-bp) with that of P. seriolae (GenBank accession no. {"type":"entrez-nucleotide","attrs":{"text":"FJ155811","term_id":"205318602"}}FJ155811). This nematode species has been newly added to the Korean nematode fauna.