On the cover
Microtubules (green) in a two-cell stage mouse embryo self-assemble into a mitotic spindle from multiple microtubule-organizing centers (red), a mechanism similar to meiotic spindle formation. Courtois et al. reveal that cells gradually transition from meiosis to mitosis over the first few divisions of embryonic development. Chromosomes in both the cells and polar body are stained blue.
Image © 2012 Courtois et al.
See page 357.
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkEditorial Board
In This Issue
People & Ideas
In contrast to ATM-null mice, mice expressing a kinase-dead ATM variant exhibit embryonic lethality, associated with greater deficiency in homologous recombination.
Expression of a kinase-deficient ATM protein leads to severe genomic instability and embryonic lethality.
Conformational changes in tubulin in GMPCPP and GDP-taxol microtubules observed by cryoelectron microscopy
Cryoelectron microscopy reveals conformational changes at the contacts between tubulins between GMPCPP and GDP-taxol microtubules.
Docking of large dense-core vesicles is reduced by cleavage of any of the neuronal SNARE complex proteins: synaptobrevin, syntaxin, or SNAP-25.
Asymmetric stem cell divisions controlled by Apc in the intestinal crypt result in regulated, anisotropic movement of daughter cells away from the niche.
Motor-driven motility of fungal nuclear pores organizes chromosomes and fosters nucleocytoplasmic transport
Instead of the structural nuclear lamina seen in animals, fungi use motor-driven motility of nuclear pore complexes to ensure chromosome organization and efficient nuclear transport.
The transition from meiotic to mitotic spindle assembly is gradual during early mammalian development
The transition from a meiotic-like spindle formation characterized by lack of centrioles to a typical mitotic spindle occurs gradually in embryos during the preimplantation stage.
ADP ribosylation adapts an ER chaperone response to short-term fluctuations in unfolded protein load
Inactivating ADP ribosylation of the ER chaperone BiP is a rapidly reversible mechanism for buffering acute changes in unfolded protein load.
The Hsp70 system recruits ClpB/Hsp104 to the surface of stress-induced protein aggregates and prion fibrils.
Agrin regulates CLASP2-mediated capture of microtubules at the neuromuscular junction synaptic membrane
Agrin regulates acetylcholine receptors at the neuromuscular junction by locally stabilizing microtubules through the plus end tracking proteins CLASP2 and CLIP-170.
The RNA helicase DDX6 promotes HIV-1 assembly in a co-opted cellular complex containing P body proteins and ABCE1.
Using transmission electron microscopy, automated data collection, and image stitching, biological specimens as large as one square millimeter can be ultrastructurally mapped at nanometer resolution.