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Viruses are known to co-opt host machinery for translation initiation, but less is known about which host factors are required for the formation of ribosomes used to synthesize viral proteins. Using a loss of function CRISPR screen, we show that synthesis of a flavivirus encoded reporter depends on multiple host factors, including several 60S ribosome biogenesis proteins. Viral phenotyping revealed that two of these factors, SBDS, a known ribosome biogenesis factor, and the relatively uncharacterized protein SPATA5, were broadly required for replication of flaviviruses, coronaviruses, alphaviruses, paramyxoviruses, an enterovirus, and a poxvirus. Mechanistic studies revealed that loss of SPATA5 caused defects in ribosomal RNA processing and ribosome assembly, suggesting that this human protein may be a functional ortholog of yeastDrg1. These studies implicate specific ribosome biogenesis proteins as viral host dependency factors that are required for synthesis of virally encoded protein and accordingly, optimal viral replication.

A subset of small cell lung cancer (SCLC) shows clinically relevant response to PARP1 inhibitors (PARPi). However,BRCA1/2mutations are not commonly found in SCLC, and the underlying mechanism(s) of PARPi sensitivity in SCLC is poorly understood. We performed quantitative proteomic analyses and identified proteomic changes that signify PARPi responses in a large panel of molecularly annotated patient-derived SCLC lines. We found that the toxicity of PARPi in SCLC could be explained, at least in part, by the PARPi-induced degradation of key lineage-specific oncoproteins including ASCL1, NEUROD1, POU2F3, KDM4A, and KDM5B. Importantly, the degradation of these SCLC lineage-specific oncoproteins could also be induced by commonly used chemotherapeutic agents. Biochemical experiments showed that PARPi-induced activation of E3 ligases (e.g., HUWE1 and RNF8) mediated the ubiquitin-proteasome system (UPS)-dependent degradation of these oncoproteins. Interestingly, although PARPi resulted in a general DNA damage response in SCLC cells, this signal is sensed by different SCLC cell lines to generate a cell-specific response. The dissection of the cell-specific oncoprotein degradation response led to the identification of potentially predictive biomarkers for PARPi in SCLC. The combination of PARPi and agents targeting these pathways led to dramatically improved cytotoxicity in SCLC. PARPi-induced degradation of lineage-specific oncoproteins therefore represents a novel mechanism to explain the efficacy of PARPi in tumors withoutBRCA1/2mutations.HighlightsQuantitative mass spectrometric analysis identifies proteomic changes associated with PARPi treatment in a large panel of SCLC cell lines.PARPi leads to the degradation of lineage-specific oncoproteins (e.g., ASCL1 and KDM4A) via the DNA damage responsive E3 ubiquitin ligases (e.g., HUWE1 and RNF8).A combination of PARPi and agents targeting the lineage-specific oncoproteins offers a more complete and durable therapeutic response in SCLC, compared to PARPi alone.Expression of lineage-specific oncoproteins and the associated ubiquitination machinery are predictive biomarkers for PARPi-induced cytotoxicity in SCLC.

Rapidly proliferating cells produce more ribosomes to translate sufficient proteins for cell growth. One of the first and rate limiting steps in translation initiation is the interaction of the small ribosomal subunit with mRNAs. Therefore, effective small ribosomal subunit biogenesis is critical for translation initiation efficiency. Here we report the identification of the zinc finger protein 692 (ZNF692), a MYC-induced nucleolar scaffold that coordinates the final steps in the biogenesis of the small 40S ribosome. ZNF692 forms a complex with rRNA, the 90S processome and the nucleolar exosome in the granular component of the nucleolus creating a hub specialized in the final steps of 18S processing and small ribosomal subunit maturation. Cancer cells are more reliant on ZNF692 for increased translation than normal cells. We propose that MYC increases translation efficiency by promoting the expression of ZNF692, adjusting the translation rate to the increase in mRNA transcription induced by MYC.

Gamete formation from germline stem cells (GSCs) is essential for sexual reproduction. However, the regulation of GSC differentiation is incompletely understood. Set2, which deposits H3K36me3 modifications, is required for GSC differentiation during Drosophila oogenesis. We discovered that the H3K36me3 reader Male-specific lethal 3 (Msl3) and histone acetyltransferase complex Ada2a-containing (ATAC) cooperate with Set2 to regulate GSC differentiation in female Drosophila. Msl3, acting independently of the rest of the male-specific lethal complex, promotes transcription of genes, including a germline-enriched ribosomal protein S19 paralog RpS19b. RpS19b upregulation is required for translation of RNA-binding Fox protein 1 (Rbfox1), a known meiotic cell cycle entry factor. Thus, Msl3 regulates GSC differentiation by modulating translation of a key factor that promotes transition to an oocyte fate.

Short-term exposures to air pollutants such as particulate matter (PM) have been associated with increased risk for symptoms of acute respiratory infections (ARIs). Less well understood is how long-term exposures to fine PM (PM2.5) might increase risk of ARIs and their symptoms. This research uses georeferenced Demographic Health Survey (DHS) data from Kenya (2014) along with a remote sensing based raster of PM2.5 concentrations to test associations between PM2.5 exposure and ARI symptoms in children for up to 12 monthly lags.Predicted PM2.5 concentrations were extracted from raster of monthly averages for latitude/longitude locations of survey clusters. These data and other environmental and demographic data were used in a logistic regression model of ARI symptoms within a distributed lag nonlinear modeling framework (DLNM) to test lag associations of PM2.5 exposure with binary presence/absence of ARI symptoms in the previous two weeks.Out of 7036 children under five for whom data were available, 46.8% reported ARI symptoms in the previous two weeks. Exposure to PM2.5 within the same month and as an average for the previous 12 months was 18.31 and 22.1 µg/m3, respectively, far in excess of guidelines set by the World Health Organization. One-year average PM2.5 exposure was higher for children who experienced ARI symptoms compared with children who did not (22.4 vs. 21.8 µg/mLong-term exposure to high concentrations of PM2.5 may increase risk for acute respiratory problems in small children. However, more work should be carried out to increase capacity to accurately measure air pollutants in emerging economies such as Kenya.

Emerging evidence suggests that ribosome heterogeneity may have important functional consequences in the translation of specific mRNAs within different cell types and under various conditions. Ribosome heterogeneity comes in many forms, including post-translational modification of ribosome proteins (RPs), absence of specific RPs and inclusion of different RP paralogs. The Drosophila genome encodes two RpS5 paralogs: RpS5a and RpS5b. While RpS5a is ubiquitously expressed, RpS5b exhibits enriched expression in the reproductive system. Deletion of RpS5b results in female sterility marked by developmental arrest of egg chambers at stages 7-8, disruption of vitellogenesis and posterior follicle cell (PFC) hyperplasia. While transgenic rescue experiments suggest functional redundancy between RpS5a and RpS5b, molecular, biochemical and ribo-seq experiments indicate that RpS5b mutants display increased rRNA transcription and RP production, accompanied by increased protein synthesis. Loss of RpS5b results in microtubule-based defects and in mislocalization of Delta and Mindbomb1, leading to failure of Notch pathway activation in PFCs. Together, our results indicate that germ cell-specific expression of RpS5b promotes proper egg chamber development by ensuring the homeostasis of functional ribosomes.

Introduction: Short-term exposures to air pollutants such as particulate matter (PM) have been associated with increased risk for symptoms of acute respiratory infections (ARIs). Less well understood is how long-term exposures to fine PM (PM2.5) might increase risk of ARIs and their symptoms. This research uses georeferenced Demographic Health Survey (DHS) data from Kenya (2014) along with a remote sensing based raster of PM2.5 concentrations to test associations between PM2.5 exposure and ARI symptoms in children for up to 12 monthly lags. Methods: Predicted PM2.5 concentrations were extracted from raster of monthly averages for latitude/longitude locations of survey clusters. These data and other environmental and demographic data were used in a logistic regression model of ARI symptoms within a distributed lag nonlinear modeling framework (DLNM) to test lag associations of PM2.5 exposure with binary presence/absence of ARI symptoms in the previous two weeks. Results: Out of 7036 children under five for whom data were available, 46.8% reported ARI symptoms in the previous two weeks. Exposure to PM2.5 within the same month and as an average for the previous 12 months was 18.31 and 22.1 µg/m3, respectively, far in excess of guidelines set by the World Health Organization. One-year average PM2.5 exposure was higher for children who experienced ARI symptoms compared with children who did not (22.4 vs. 21.8 µg/m3, p < 0.0001.) Logistic regression models using the DLNM framework indicated that while PM exposure was not significantly associated with ARI symptoms for early lags, exposure to high concentrations of PM2.5 (90th percentile) was associated with elevated odds for ARI symptoms along a gradient of lag exposure time even when controlling for age, sex, types of cooking fuels, and precipitation. Conclusions: Long-term exposure to high concentrations of PM2.5 may increase risk for acute respiratory problems in small children. However, more work should be carried out to increase capacity to accurately measure air pollutants in emerging economies such as Kenya.

SummaryGamete formation from germline stem cells (GSCs) is essential for sexual reproduction. However, the regulation of GSC differentiation and meiotic entry are incompletely understood. Set2, which deposits H3K36me3 modifications, is required for differentiation of GSCs duringDrosophilaoogenesis. We discovered that the H3K36me3 reader Male-specific lethal 3 (MSL3) and the histone acetyltransferase complex Ada2a-containing (ATAC) cooperate with Set2 to regulate entry into meiosis in femaleDrosophila. MSL3 expression is restricted to the mitotic and early meiotic stages of the female germline, where it promotes transcription of genes encoding synaptonemal complex components and a germline enrichedribosomal protein S19paralog,RpS19b.RpS19bupregulation is required for translation of Rbfox1, a known meiotic cell cycle entry factor. Thus, MSL3 is a master regulator of meiosis, coordinating the expression of factors required for recombination and GSC differentiation. We find that MSL3 is expressed during mouse spermatogenesis, suggesting a conserved function during meiosis.

This study explores how ethnic restaurants serve their role as ‘tourism at home’, by investigating customers’ motivation to visit ethnic restaurants, especially in relation to tourism. This study adopted a grounded theory approach, using semi-structured interviews composed of two phases. The first phase of interviews was conducted with 18 British people who had experienced at least one of the four ethnic restaurants, Chinese, Japanese, Thai or Korean. The second phase of interviews was conducted with 12 British people who were actually visiting one of the origin countries of those restaurants, Korea, to see if people share the same motivation to visit ethnic restaurants as travel motivation. Six common motivational factors between visiting ethnic restaurants and travel (i.e., to change/ escape from the routine, to experience something new/ different, to experience and learn about another culture, curiosity/ desire to explore unknown, togetherness, and travelling itself) were established through findings, and the relationships between motivation to visit ethnic restaurants and tourism, and how they influence each other were identified.

Mutations in PINK1 (PTEN-induced putative kinase 1) are tightly linked to autosomal recessive Parkinson disease (PD). Although more than 50 mutations in PINK1 have been discovered, the role of these mutations in PD pathogenesis remains poorly understood. Here, we characterized 17 representative PINK1 pathogenic mutations in both mammalian cells and Drosophila. These mutations did not affect the typical cleavage patterns and subcellular localization of PINK1 under both normal and damaged mitochondria conditions in mammalian cells. However, PINK1 mutations in the kinase domain failed to translocate Parkin to mitochondria and to induce mitochondrial aggregation. Consistent with the mammalian data, Drosophila PINK1 mutants with mutations in the kinase domain (G426D and L464P) did not genetically interact with Parkin. Furthermore, PINK1-null flies expressing the transgenic G426D mutant displayed defective phenotypes with increasing age, whereas L464P mutant-expressing flies exhibited the phenotypes at an earlier age. Collectively, these results strongly support the hypothesis that the kinase activity of PINK1 is essential for its function and for regulating downstream Parkin functions in mitochondria. We believe that this study provides the basis for understanding the molecular and physiological functions of various PINK1 mutations and provides insights into the pathogenic mechanisms of PINK1-linked PD.