Common fragile sites (CFSs) can drive genomic instability. Debatisse, Dutrillaux and colleagues now use the replication features of mapped CFSs in lymphocytes to rapidly identify CFSs in fibroblasts. Image from iStockphoto, by Don Komarechka (http://www.donkom.ca). pp 1421–1423

The C-terminus of α-tubulin can be modified by addition of a tyrosine residue. Roll-Mecak and colleagues present the crystal structure of tubulin tyrosine ligase, providing insight into how this enzyme recognizes its substrate. Image created by Janet Iwasa and Antonina Roll-Mecak. pp 1250–1258

Competition between ADARs and the RNAi machinery has been suggested by previous work in Caenorhabditis elegans. Fire and colleagues now show that ADARs can prevent access to the RNAi pathway for an extensive population of dsRNAs. Artwork by Erin Dewalt. pp 1094–1101

Chromatin has been implicated in regulating pre-mRNA splicing, but their precise relationship has been unclear. Andrau, Ferrier, Carmo-Fonseca and colleagues now show that pre-mRNA splicing influences H3K36 trimethylation by recruiting methyltransferase HYPB/Setd2. Photograph by Kevin McElheran. http://poetryofmotion.com. pp 977–983

Rubisco plays a central role in photosynthetic carbon fixation. Bracher, Hayer-Hartl and colleagues now present the crystal structure of the large subunits in form I Rubisco bound to the dedicated chaperone RbcX, revealing how the latter assists octamer assembly. Symmetric motifs in the cover image by Erin Dewalt represent the octamer. pp 875–880

The RGS family is involved in regulating G protein signaling. Using computational analysis coupled with examination of RGS activity, Arshavsky and colleagues now highlight a group of variable residues that together provide a "blueprint" for specific G protein recognition. Image by ImageMediaGroup from www.istockphoto.com. pp 846–853

Using polarized fluorescence microscopy, Kampmann, Atkinson, Mattheyses and Simon now examine the orientation of nucleoporins in the nuclear pore complex in live cells. The nuclear pore is represented in the cover image showing the Pantheon in Rome. Photograph by Terraxplorer from www.istockphoto.com, final design by Erin Dewalt. pp 643–649

The prokaryotic CRISPR system uses small RNA guides to protect against invaders and depends on a ribonucleoprotein complex called Cascade. Recognition of DNA targets by Cascade, as well as the overall structure of the complex, are now examined by van der Oost and colleagues. Photograph by ooyoo from www.istockphoto.com; final design by Erin Dewalt. pp 529–536

Surewicz and colleagues now probe the structure of infectious PrPSc fibrils purified from mouse brains. Prion fibrils are represented in the photograph by Kevin Hedquist, http://www.wix.com/khedquist/kevin-hedquist-2. pp 504–506

Hsc70-mediated disassembly of clathrin coats at a single particle level, represented on the cover by the dispersal of dandelion seeds from individual flowerheads, is now examined by Kirchhausen and colleagues. Photograph by pkruger from www.istockphoto.com; final design by Erin Dewalt. pp 295–301

The interactions of proteins with solvent molecules have previously not been well understood, largely due to technical challenges. Now Wand and colleagues utilize reverse micelles to characterize the hydration sites of ubiquitin and observe water molecules clustering in previously unseen patterns. Cover image from istockphoto.com. pp 245–249

Mitochondria undergo cycles of fission and fusion and the dynamin-like protein, Dnm1, localizes to division sites. Hinshaw and colleagues now solve the cryo-EM structure of Dnm1-lipid tubes and compare it to dynamin. Upon GTP addition, the Dnm1-lipid tubes constrict, suggesting that Dnm1 can impart a large contractile force. Cover image represents Dnm1 constriction; photograph by Paul Rushton, image from www.123rf.com; final design by Erin Dewalt.pp 20–26