A non‐canonical role of the p97 complex in RIG‐I antiviral signaling

RIG‐I is a well‐studied sensor of viral RNA that plays a key role in innate immunity. p97 regulates a variety of cellular events such as protein quality control, membrane reassembly, DNA repair, and the cell cycle. Here, we report a new role for p97 with Npl4‐Ufd1 as its cofactor in reducing antiviral innate immune responses by facilitating proteasomal degradation of RIG‐I. The p97 complex is able to directly bind both non‐ubiquitinated RIG‐I and the E3 ligase RNF125, promoting K48‐linked ubiquitination of RIG‐I at residue K181. Viral infection significantly strengthens the interaction between RIG‐I and the p97 complex by a conformational change of RIG‐I that exposes the CARDs and through K63‐linked ubiquitination of these CARDs. Disruption of the p97 complex enhances RIG‐I antiviral signaling. Consistently, administration of compounds targeting p97 ATPase activity was shown to inhibit viral replication and protect mice from vesicular stomatitis virus (VSV) infection. Overall, our study uncovered a previously unrecognized role for the p97 complex in protein ubiquitination and revealed the p97 complex as a potential drug target in antiviral therapy.     

Genomic organization of the human interleukin-12 receptor β2-chain gene

 The interleukin-12 receptor (IL-12R) is composed of two subunits, referred to as β1 and β2. Both chains are necessary for high-affinity IL-12 binding and signalling, although only the IL-12Rβ2 chain contains the intracellular tyrosine residues responsible for STAT4 activation. This study presents the intron-exon organization of the human IL-12Rβ2-chain gene. Polymerase chain reaction (PCR) primers designed across the cDNA (U46198) were used to trace introns, by comparing PCR product sizes obtained using cDNA and genomic DNA as templates. PCR products spanning introns were sequenced to determine the exact splice sites and flanking regions. The coding region of the gene was found to consist of 15 exons and 14 introns. All intron-exon boundaries are consistent with the consensus sequence for splice junctions (5′ GT/AG 3′). Comparison of the intron-exon organization with the human GCSFR gene indicated a remarkably well conserved genomic organization between these two class I cytokine receptors. Interestingly, we identified an alternatively spliced mRNA, encoding a putative, truncated protein, lacking all signalling potential. Received: 21 July 1999 / Revised: 2 September 1999     

Tetratricopeptide Repeat Domain 9A Negatively Regulates Estrogen Receptor Alpha Activity

Tetratricopeptide repeat domain 9A (TTC9A) is a target gene of estrogen and progesterone. It is over-expressed in breast cancer. However, little is known about the physiological function of TTC9A. The objectives of this study were to establish a Ttc9a knockout mouse model and to study the consequence of Ttc9a gene inactivation. The Ttc9a targeting vector was generated by replacing the Ttc9a exon 1 with a neomycin cassette. The mice homozygous for Ttc9a exon 1 deletion appear to grow normally and are fertile. However, further characterization of the female mice revealed that Ttc9a deficiency is associated with greater body weight, bigger thymus and better mammary development in post-pubertal mice. Furthermore, Ttc9a deficient mammary gland was more responsive to estrogen treatment with greater mammary ductal lengthening, ductal branching and estrogen target gene induction. Since Ttc9a is induced by estrogen in estrogen target tissues, these results suggest that Ttc9a is a negative regulator of estrogen function through a negative feedback mechanism. This is supported by in vitro evidence that TTC9A over-expression attenuated ERα activity in MCF-7 cells. Although TTC9A does not bind to ERα or its chaperone protein Hsp90 directly, TTC9A strongly interacts with FKBP38 and FKBP51, both of which interact with ERα and Hsp90 and modulate ERα activity. It is plausible therefore that TTC9A negatively regulates ERα activity through interacting with co-chaperone proteins such as FKBP38 and FKBP51.     

A GFP-MAP4 reporter gene for visualizing cortical microtubule rearrangements in living epidermal cells

Microtubules influence morphogenesis by forming distinct geometrical arrays in the cell cortex, which in turn affect the deposition of cellulose microfibrils. Although many chemical and physical factors affect microtubule orientation, it is unclear how cortical microtubules in elongating cells maintain their ordered transverse arrays and how they reorganize into new geometries. To visualize these reorientations in living cells, we constructed a microtubule reporter gene by fusing the microtubule binding domain of the mammalian microtubule-associated protein 4 (MAP4) gene with the green fluorescent protein (GFP) gene, and transient expression of the recombinant protein in epidermal cells of fava bean was induced. The reporter protein decorates microtubules in vivo and binds to microtubules in vitro. Confocal microscopy and time-course analysis of labeled cortical arrays along the outer epidermal wall revealed the lengthening, shortening, and movement of microtubules; localized microtubule reorientations; and global microtubule reorganizations. The global microtubule orientation in some cells fluctuates about the transverse axis and may be a result of a cyclic self-correcting mechanism to maintain a net transverse orientation during cellular elongation.     

Live Tracking of Inter-organ Communication by Endogenous Exosomes In Vivo

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Nested assemblages of Orthoptera species in the Netherlands: the importance of habitat features and life-history traits

Aim Species communities often exhibit nestedness, the species found in species‐poor sites representing subsets of richer ones. In the Netherlands, where intensification of land use has led to severe fragmentation of nature, we examined the degree of nestedness in the distribution of Orthoptera species. An assessment was made of how environmental conditions and species life‐history traits are related to this pattern, and how variation in sampling intensity across sites may influence the observed degree of nestedness. Location The analysis includes a total of 178 semi‐natural sites in the Pleistocene sand region of the Netherlands. Methods A matrix recording the presence or absence of all Orthoptera species in each site was compiled using atlas data. Additionally, separate matrices were constructed for the species of suborders Ensifera and Caelifera. The degree of nestedness was measured using the binmatnest calculator. binmatnest uses an algorithm to sort the matrices to maximal nestedness. We used Spearman’s rank correlations to evaluate whether sites were sorted by area, isolation or habitat heterogeneity, and whether species were sorted by their dispersal ability, rate of development or degree of habitat specificity. Results We found the Orthoptera assemblages to be significantly nested. The rank correlation between site order and sampling intensity was high. The degree of nestedness was lower, but remained significant when under‐ and over‐sampled sites were excluded from the analysis. Site order was strongly correlated with both size of sample site and number of habitat types per site. Rank correlations showed that species were probably ordered by variation in habitat specificity, rather than by variation in dispersal capacity or rate of development of the species. Main conclusions Variation in sampling intensity among sites had a strong impact on the observed degree of nestedness. Nestedness in habitats may underlie the observed nestedness within the Orthoptera assemblages. Habitat heterogeneity is closely related to site area, which suggests that several large sites should be preserved, rather than many small sites. Furthermore, the results corroborate a focus of nature conservation policy on sites where rare species occur, as long as the full spectrum of habitat conditions and underlying ecological processes is secured.     

Predicting loneliness with polygenic scores of social,psychological and psychiatric traits

Loneliness is a heritable trait that accompanies multiple disorders. The association between loneliness and mental health indices may partly be due to inherited biological factors. We constructed polygenic scores for 27 traits related to behavior, cognition and mental health and tested their prediction for self‐reported loneliness in a population‐based sample of 8798 Dutch individuals. Polygenic scores for major depressive disorder (MDD), schizophrenia and bipolar disorder were significantly associated with loneliness. Of the Big Five personality dimensions, polygenic scores for neuroticism and conscientiousness also significantly predicted loneliness, as did the polygenic scores for subjective well‐being, tiredness and self‐rated health. When including all polygenic scores simultaneously into one model, only 2 major depression polygenic scores remained as significant predictors of loneliness. When controlling only for these 2 MDD polygenic scores, only neuroticism and schizophrenia remain significant. The total variation explained by all polygenic scores collectively was 1.7%. The association between the propensity to feel lonely and the susceptibility to psychiatric disorders thus pointed to a shared genetic etiology. The predictive power of polygenic scores will increase as the power of the genome‐wide association studies on which they are based increases and may lead to clinically useful polygenic scores that can inform on the genetic predisposition to loneliness and mental health.     

MAINTENANCE OF GENETIC VARIATION IN HUMAN PERSONALITY: TESTING EVOLUTIONARY MODELS BY ESTIMATING HERITABILITY DUE TO COMMON CAUSAL VARIANTS AND INVESTIGATING THE EFFECT OF DISTANT INBREEDING

Personality traits are basic dimensions of behavioral variation, and twin, family, and adoption studies show that around 30% of the between‐individual variation is due to genetic variation. There is rapidly growing interest in understanding the evolutionary basis of this genetic variation. Several evolutionary mechanisms could explain how genetic variation is maintained in traits, and each of these makes predictions in terms of the relative contribution of rare and common genetic variants to personality variation, the magnitude of nonadditive genetic influences, and whether personality is affected by inbreeding. Using genome‐wide single nucleotide polymorphism (SNP) data from > 8000 individuals, we estimated that little variation in the Cloninger personality dimensions (7.2% on average) is due to the combined effect of common, additive genetic variants across the genome, suggesting that most heritable variation in personality is due to rare variant effects and/or a combination of dominance and epistasis. Furthermore, higher levels of inbreeding were associated with less socially desirable personality trait levels in three of the four personality dimensions. These findings are consistent with genetic variation in personality traits having been maintained by mutation–selection balance.     

The impact of genetic diversity in protozoa on molecular diagnostics

Detection of intestinal parasitic protists, commonly referred to as 'intestinal protozoa,' by PCR is increasingly used not only for identification or confirmation but also as a first-line diagnostic tool. Apart from the ability to sample correctly and extract parasite DNA directly from faeces, primer and probe specificity and sensitivity affect predictive values and hence the utility of diagnostic assays. Molecular characterization of intestinal protists is necessary to design primers and probes because this is the basic material for current and future improved diagnostic PCRs for either detecting all genetic variants or specifically differentiating among such variants. As an example, this paper highlights the existence of interspecific and intraspecific genetic diversity among intestinal, unicellular parasites and its implications for nucleic acid-based diagnostic assays.