We identify a cytochrome P450 gene (CYP6AE14) from cotton bollworm (Helicoverpa armigera), which permits this herbivore to tolerate otherwise inhibitory concentrations of the cotton metabolite, gossypol. CYP6AE14 is highly expressed in the midgut and its expression correlates with larval growth when gossypol is included in the diet. When larvae are fed plant material expressing double-stranded RNA (dsRNA) specific to CYP6AE14, levels of this transcript in the midgut decrease and larval growth is retarded. Both effects are more dramatic in the presence of gossypol. As a glutathione-S-transferase gene (GST1) is silenced in GST1 dsRNA-expressing plants, feeding insects plant material expressing dsRNA may be a general strategy to trigger RNA interference and could find applications in entomological research and field control of insect pests.

Voltage-gated sodium (Nav) channels are essential for the rapid depolarization of nerve and muscle1, and are important drug targets2. A family of bacterial Nav channels, exemplified by NaChBac (Na+-selective Channel of Bacteria)3, provides a good model system for structure-function analysis. Here we report the crystal structure of NavAP, a NaChBac orthologue from marine bacteria alpha proteobacterium HIMB114, at 3.05 Å resolution. The channel comprises an asymmetric tetramer. The carbonyl oxygen atoms of Thr178 and Leu179 constitute an inner site within the selectivity filter (178TLSSWE183) where a Ca2+ can bind and resides in the crystal structure. The outer mouth of the Na+ selectivity filter, defined by Ser181 and Glu183, is closed, as is the activation gate at the intracellular side of the pore. The voltage sensors adopt a depolarized conformation with all the gating charges exposing to the extracellular side. We hypothesize that NavAP is captured in an inactivated conformation. Comparison of NavAP with NavAb4 reveals significant conformational rearrangements that may underlie the electromechanical coupling mechanism of voltage-gated channels.

TAL (transcription activator–like) effectors, secreted by phytopathogenic bacteria, recognize host DNA sequences through a central domain of tandem repeats. Each repeat comprises 33 to 35 conserved amino acids and targets a specific base pair by using two hypervariable residues [known as repeat variable diresidues (RVDs)] at positions 12 and 13. Here, we report the crystal structures of an 11.5-repeat TAL effector in both DNA-free and DNA-bound states. Each TAL repeat comprises two helices connected by a short RVD-containing loop. The 11.5 repeats form a right-handed, superhelical structure that tracks along the sense strand of DNA duplex, with RVDs contacting the major groove. The 12th residue stabilizes the RVD loop, whereas the 13th residue makes a base-specific contact. Understanding DNA recognition by TAL effectors may facilitate rational design of DNA-binding proteins with biotechnological applications.

SUMMARY The melanoma antigen (MAGE) family consists of more than 60 genes, many of which are cancer-testis antigens that are highly expressed in cancer and play a critical role in tumorigenesis. However, the biochemical and cellular functions of this enigmatic family of proteins have remained elusive. Here, we identify really interesting new gene (RING) domain proteins as binding partners for MAGE family proteins. Multiple MAGE family proteins bind E3 RING ubiquitin ligases with specificity. The crystal structure of one of these MAGE-RING complexes, MAGE-G1-NSE1, reveals structural insights into MAGE family proteins and their interaction with E3 RING ubiquitin ligases. Biochemical and cellular assays demonstrate that MAGE proteins enhance the ubiquitin ligase activity of RING domain proteins. For example, MAGE-C2-TRIM28 is shown to target p53 for degradation in a proteasome-dependent manner, consistent with its tumorigenic functions. These findings define a biochemical and cellular function for the MAGE protein family.

Pattern recognition receptors confer plant resistance to pathogen infection by recognizing the conserved pathogen-associated molecular patterns. The cell surface receptor chitin elicitor receptor kinase 1 of Arabidopsis (AtCERK1) directly binds chitin through its lysine motif (LysM)-containing ectodomain (AtCERK1-ECD) to activate immune responses. The crystal structure that we solved of an AtCERK1-ECD complexed with a chitin pentamer reveals that their interaction is primarily mediated by a LysM and three chitin residues. By acting as a bivalent ligand, a chitin octamer induces AtCERK1-ECD dimerization that is inhibited by shorter chitin oligomers. A mutation attenuating chitin-induced AtCERK1-ECD dimerization or formation of nonproductive AtCERK1 dimer by overexpression of AtCERK1-ECD compromises AtCERK1-mediated signaling in plant cells. Together, our data support the notion that chitin-induced AtCERK1 dimerization is critical for its activation.

Abscisic acid (ABA) is an important phytohormone that regulates plant stress responses. Proteins from the PYR-PYL-RCAR family were recently identified as ABA receptors. Upon binding to ABA, a PYL protein associates with type 2C protein phosphatases (PP2Cs) such as ABI1 and ABI2, inhibiting their activity; the molecular mechanisms by which PYLs mediate ABA signaling remain unknown, however. Here we report three crystal structures: apo-PYL2, (+)-ABA-bound PYL2 and (+)-ABA-bound PYL1 in complex with phosphatase ABI1. Apo-PYL2 contains a pocket surrounded by four highly conserved surface loops. In response to ABA binding, loop CL2 closes onto the pocket, creating a surface that recognizes ABI1. In the ternary complex, the CL2 loop is located near the active site of ABI1, blocking the entry of substrate proteins. Together, our data reveal the mechanisms by which ABA regulates PYL-mediated inhibition of PP2Cs.

The plant root cap mediates the direction of root tip growth and protects internal cells. Root cap cells are continuously produced from distal stem cells, and the phytohormone auxin provides position information for root distal organization. Here, we identify the Arabidopsis thaliana auxin response factors ARF10 and ARF16, targeted by microRNA160 (miR160), as the controller of root cap cell formation. The Pro 35S :MIR160 plants, in which the expression of ARF10 and ARF16 is repressed, and the arf10-2 arf16-2 double mutants display the same root tip defect, with uncontrolled cell division and blocked cell differentiation in the root distal region and show a tumor-like root apex and loss of gravity-sensing. ARF10 and ARF16 play a role in restricting stem cell niche and promoting columella cell differentiation; although functionally redundant, the two ARFs are indispensable for root cap development, and the auxin signal cannot bypass them to initiate columella cell production. In root, auxin and miR160 regulate the expression of ARF10 and ARF16 genes independently, generating a pattern consistent with root cap development. We further demonstrate that miR160-uncoupled production of ARF16 exerts pleiotropic effects on plant phenotypes, and miR160 plays an essential role in regulating Arabidopsis development and growth.

Displays are basic building blocks of modern electronics 1,2. Integrating displays into textiles 17 offers exciting opportunities for smart electronic textiles-the ultimate form of wearables 18 poised to change the way we interact with electronic devices 3-6. Display textiles serve to bridge human-machine interactions 7-9 , offering for instance, a real-time communication tool for individuals with voice or speech disorders. Electronic textiles capable of communicating 10 , sensing 11,12 and supplying electricity 13,14 have been reported previously. However, textiles 22 with functional, large-area displays have not been achieved so far because obtaining small illuminating units that are both durable and easy to assemble over a wide area is challenging. Here, we report a 6 m (L) × 25 cm (W) display textile containing 5×10 5 electroluminescent (EL) units narrowly spaced to ~800 μm. Weaving conductive weft and luminescent warp fibres forms micron-scale EL units at the weft-warp contact points. Brightness between EL units deviates by < 6.3% and remains stable even when the textile is bent, stretched or pressed. We attribute this uniform and stable lighting to the smooth luminescent coating around the 2 warp fibres and homogenous electric field distribution at the contact points. Our display textile is flexible and breathable and withstands repeatable machine-washing, making them suitable for practical applications. We show an integrated textile system consisting of display, 32 keyboard and power supply can serve as a communication tool, which could potentially drive 33 the Internet of Things in various areas including healthcare. Our approach unifies the 34 fabrication and function of electronic devices with textiles, and we expect weaving fibre 35 materials to shape the next-generation electronics.