Faced with inequality: chicken do not have a general dosage compensation of sex-linked genes

<p>Abstract</p> <p>Background</p> <p>The contrasting dose of sex chromosomes in males and females potentially introduces a large-scale imbalance in levels of gene expression between sexes, and between sex chromosomes and autosomes. In many organisms, dosage compensation has thus evolved to equalize sex-linked gene expression in males and females. In mammals this is achieved by X chromosome inactivation and in flies and worms by up- or down-regulation of X-linked expression, respectively. While otherwise widespread in systems with heteromorphic sex chromosomes, the case of dosage compensation in birds (males ZZ, females ZW) remains an unsolved enigma.</p> <p>Results</p> <p>Here, we use a microarray approach to show that male chicken embryos generally express higher levels of Z-linked genes than female birds, both in soma and in gonads. The distribution of male-to-female fold-change values for Z chromosome genes is wide and has a mean of 1.4–1.6, which is consistent with absence of dosage compensation and sex-specific feedback regulation of gene expression at individual loci. Intriguingly, without global dosage compensation, the female chicken has significantly lower expression levels of Z-linked compared to autosomal genes, which is not the case in male birds.</p> <p>Conclusion</p> <p>The pronounced sex difference in gene expression is likely to contribute to sexual dimorphism among birds, and potentially has implication to avian sex determination. Importantly, this report, together with a recent study of sex-biased expression in somatic tissue of chicken, demonstrates the first example of an organism with a lack of global dosage compensation, providing an unexpected case of a viable system with large-scale imbalance in gene expression between sexes.</p

The German National Pandemic Cohort Network (NAPKON): rationale, study design and baseline characteristics

Schons M, Pilgram L, Reese J-P, et al. The German National Pandemic Cohort Network (NAPKON): rationale, study design and baseline characteristics. European Journal of Epidemiology . 2022.The German government initiated the Network University Medicine (NUM) in early 2020 to improve national research activities on the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic. To this end, 36 German Academic Medical Centers started to collaborate on 13 projects, with the largest being the National Pandemic Cohort Network (NAPKON). The NAPKON's goal is creating the most comprehensive Coronavirus Disease 2019 (COVID-19) cohort in Germany. Within NAPKON, adult and pediatric patients are observed in three complementary cohort platforms (Cross-Sectoral, High-Resolution and Population-Based) from the initial infection until up to three years of follow-up. Study procedures comprise comprehensive clinical and imaging diagnostics, quality-of-life assessment, patient-reported outcomes and biosampling. The three cohort platforms build on four infrastructure core units (Interaction, Biosampling, Epidemiology, and Integration) and collaborations with NUM projects. Key components of the data capture, regulatory, and data privacy are based on the German Centre for Cardiovascular Research. By April 01, 2022, 34 university and 40 non-university hospitals have enrolled 5298 patients with local data quality reviews performed on 4727 (89%). 47% were female, the median age was 52 (IQR 36-62-) and 50 pediatric cases were included. 44% of patients were hospitalized, 15% admitted to an intensive care unit, and 12% of patients deceased while enrolled. 8845 visits with biosampling in 4349 patients were conducted by April 03, 2022. In this overview article, we summarize NAPKON's design, relevant milestones including first study population characteristics, and outline the potential of NAPKON for German and international research activities.Trial registration https://clinicaltrials.gov/ct2/show/NCT04768998 . https://clinicaltrials.gov/ct2/show/NCT04747366 . https://clinicaltrials.gov/ct2/show/NCT04679584. © 2022. The Author(s)

Nach(t)-Musiken

Der Titel Nach(t)-Musiken greift das von Friedrich Cerha geschätzte Prinzip der Mehrfachcodierung auf. Erstens lässt er an die Notturni Gustav Mahlers denken, an eine spezifisch österreichische Klanglandschaft also. Zweitens erinnert er an die von Cerha gepflegte Praktik, des Nachts zu komponieren. Drittens klingen jene Werke nach, die eines Anstoß‘ von außen bedurften, sei es durch Skulpturen, Gedichte oder musikalisch-intertextuelle Bezüge. Der Fokus auf Instrumentalmusik lässt an eine bestimmte Klanglandschaft denken, deren Weite sich einem nunmehr 95-jährigen Künstlerleben verdankt. Sie reicht vom Neoklassizismus über den Serialismus bis zur Klangkomposition, deutet auf musikhistorische Reflektionen (von der Renaissance bis zur Wiener Schule) und gibt den Komponisten als Fährtensucher zu erkennen, der dem Reichtum der Welt unermüdlich auf der Spur ist. Kurz, Cerha ist es wie kaum jemandem gelungen, die Polarität zwischen Intellektualität wie Sinnlichkeit aufzuheben und so in neue Dimensionen des Komponierens vorzustoßen. Der Band verdankt sich einer langjährigen Zusammenarbeit des Archivs der Zeitgenossen (Krems/Donau) mit dem Fach Musikwissenschaft der Universität Siegen. Die gemeinsamen „Sommerkolloquien“ förderten die Bildung eines Kreises von ExpertInnen, die auf Augenhöhe kommunizieren

Different residues in the SARS-CoV spike protein determine cleavage and activation by the host cell protease TMPRSS2

<div><p>The spike (S) protein of severe acute respiratory syndrome coronavirus (SARS-CoV) mediates viral entry into target cells. Cleavage and activation of SARS S by a host cell protease is essential for infectious viral entry and the responsible enzymes are potential targets for antiviral intervention. The type II transmembrane serine protease TMPRSS2 cleaves and activates SARS S in cell culture and potentially also in the infected host. Here, we investigated which determinants in SARS S control cleavage and activation by TMPRSS2. We found that SARS S residue R667, a previously identified trypsin cleavage site, is also required for S protein cleavage by TMPRSS2. The cleavage fragments produced by trypsin and TMPRSS2 differed in their decoration with N-glycans, suggesting that these proteases cleave different SARS S glycoforms. Although R667 was required for SARS S cleavage by TMPRSS2, this residue was dispensable for TMPRSS2-mediated S protein activation. Conversely, residue R797, previously reported to be required for SARS S activation by trypsin, was dispensable for S protein cleavage but required for S protein activation by TMPRSS2. Collectively, these results show that different residues in SARS S control cleavage and activation by TMPRSS2, suggesting that these processes are more complex than initially appreciated.</p></div

R667 but not R797 is required for SARS S cleavage by trypsin and TMPRSS2.

<p>Plasmids encoding SARS S wt or the indicated SARS S mutants were cotransfected with TMPRSS2 plasmid or empty plasmid into 293T cells. Subsequently, the cells were treated with trypsin or PBS and SARS S cleavage was analyzed by Western blot employing anti-V5 antibody. Detection of β-actin served as loading control. The results were confirmed in two to four separate experiments. The SARS S cleavage products generated by trypsin and TMPRSS2 are indicated by black and white filled triangles, respectively.</p

Mutations R667A, T678S and R797N are compatible with robust S protein-driven cell entry.

<p>(A) 293T cells transfected to express MLV particles pseudotyped with SARS S wt or the indicated SARS S mutants and the corresponding supernatants were analyzed for expression of S protein (employing anti-V5 antibody) and MLV capsid protein (employing anti-p30 antibody) by Western blot. Cells transfected to express S protein alone or transfected with empty plasmid were used as controls. Similar results were obtained in two independent experiments. (B) 293T target cells transfected with empty plasmid (control) or ACE2 plasmid were transduced with equal volumes of pseudotypes bearing the indicated viral glycoproteins. Transduction efficiency was quantified by measuring luciferase activities in cell lysates. Results were normalized for SARS S-driven transduction of ACE2 expressing cells, which was set as 1-fold. The average of three to eight independent experiments is shown. Error bars indicate standard error of the mean (SEM).</p

Mutations K543A/R544A and R563A/K566A interfere with SARS S trafficking through the constitutive secretory pathway.

<p>(A) COS-7 cells were cotransfected with expression plasmids for SARS S wt or the indicated mutants and with a plasmid encoding YFP fused to a plasma membrane anchor (red color). After staining for SARS S with V5 antibody and anti-mouse Alexa Fluor 647 secondary antibody (green color) the cells were analyzed by confocal microscopy. Similar results were obtained in a second independent experiment. (B) The experiment was carried out as described for panel A, but GFP fused to a Golgi marker (red color) was used instead of YFP with plasma membrane anchor. The results were confirmed in a second separate experiment. For optimal visualization, colors were manually assigned with LSM Pascal 5 software version 3 and do not correspond to the actual emission spectra of YFP, GFP and Alexa Fluor 647.</p

R797 but not R667 is required for SARS S activation by TMPRSS2.

<p>293T target cells transfected with ACE2 plasmid or cotransfected with ACE2 and TMPRSS2 plasmid were pretreated with DMSO or the cathepsin B/L inhibitor MDL 28170 for 1 h before addition of equal volumes of pseudotypes bearing the indicated glycoproteins. Cellular entry was quantified by measurement of luciferase activity in cell lysates. Results were normalized for transduction of ACE2⁺, TMPRSS2^- cells in the absence of inhibitor, which was set as 1-fold. The average of three to six independent experiments is shown (R667A, n = 3; SARS S wt and VSV-G, n = 4; R797N, n = 6). Error bars indicate SEM. Statistical significance was assessed using one-tailed student’s t-est.</p