Compositionality in the language of emotion

Emotions are signaled by complex arrays of face and body actions. The main point of contention in contemporary treatments is whether these arrays are discrete, holistic constellations reflecting emotion categories, or whether they are compositional-comprised of smaller components, each of which contributes some aspect of emotion to the complex whole. We address this question by investigating spontaneous face and body displays of athletes and place it in the wider context of human communicative signals and, in particular, of language. A defining property of human language is compositionality-the ability to combine and recombine a relatively small number of elements to create a vast number of complex meaningful expressions, and to interpret them. We ask whether this property of language can be discerned in a more ancient communicative system: intense emotional displays. In an experiment, participants interpreted a range of emotions and their strengths in pictures of athletes who had just won or lost a competition. By matching participants' judgements with minutely coded features of face and body, we find evidence for compositionality. The distribution of participants' responses indicates that most of the athletes' face and body features contribute to displays of dominance or submission. More particular emotional components related, for example, to positive valence (e.g. happy) or goal obstruction (e.g. frustrated), were also found to significantly correlate with certain face and body features. We propose that the combination of features linked to broader components (i.e, dominant or submissive) and to more particular emotions (e.g, happy or frustrated) reflects more complex emotional states. In sum, we find that the corporeal expression of intense, unfiltered emotion has compositional properties, potentially providing an ancient scaffolding upon which, millions of years later, the abstract and constrained compositional system of human language could build

Complete Structural Model of Escherichia coli RNA Polymerase from a Hybrid Approach

A combination of structural approaches yields a complete atomic model of the highly biochemically characterized Escherichia coli RNA polymerase, enabling fuller exploitation of E. coli as a model for understanding transcription

Mechanism of Dis3l2 substrate recognition in the Lin28-let-7 pathway

The pluripotency factor Lin28 inhibits the biogenesis of the let-7 family of mammalian microRNAs. Lin28 is highly expressed in embryonic stem cells and has a fundamental role in regulation of development, glucose metabolism and tissue regeneration. Overexpression of Lin28 is correlated with the onset of numerous cancers, whereas let-7, a tumour suppressor, silences several human oncogenes. Lin28 binds to precursor let-7 (pre-let-7) hairpins, triggering the 3' oligo-uridylation activity of TUT4 and TUT7 (refs 10-12). The oligoU tail added to pre-let-7 serves as a decay signal, as it is rapidly degraded by Dis3l2 (refs 13, 14), a homologue of the catalytic subunit of the RNA exosome. The molecular basis of Lin28-mediated recruitment of TUT4 and TUT7 to pre-let-7 and its subsequent degradation by Dis3l2 is largely unknown. To examine the mechanism of Dis3l2 substrate recognition we determined the structure of mouse Dis3l2 in complex with an oligoU RNA to mimic the uridylated tail of pre-let-7. Three RNA-binding domains form an open funnel on one face of the catalytic domain that allows RNA to navigate a path to the active site different from that of its exosome counterpart. The resulting path reveals an extensive network of uracil-specific interactions spanning the first 12 nucleotides of an oligoU-tailed RNA. We identify three U-specificity zones that explain how Dis3l2 recognizes, binds and processes uridylated pre-let-7 in the final step of the Lin28-let-7 pathway

The crystal structure of the Argonaute2 PAZ domain reveals an RNA binding motif in RNAi effector complexes

RISC, the RNA-induced silencing complex, uses short interfering RNAs (siRNAs) or micro RNAs (miRNAs) to select its targets in a sequence-dependent manner. Key RISC components are Argonaute proteins, which contain two characteristic domains, PAZ and PIWI. PAZ is highly conserved and is found only in Argonaute proteins and Dicer. We have solved the crystal structure of the PAZ domain of Drosophila Argonaute2. The PAZ domain contains a variant of the OB fold, a module that often binds single-stranded nucleic acids. PAZ domains show low-affinity nucleic acid binding, probably interacting with the 3' ends of single-stranded regions of RNA. PAZ can bind the characteristic two-base 3' overhangs of siRNAs, indicating that although PAZ may not be a primary nucleic acid binding site in Dicer or RISC, it may contribute to the specific and productive incorporation of siRNAs and miRNAs into the RNAi pathway