Cell cycle

The Caenorhabditis elegans centrosomal protein SPD-2 is required for both pericentriolar material recruitment and centriole duplication. Pelletier, L. et al. Curr. Biol. 14, 863–873 (2004)

The authors identified SPD-2, a component of the Caenorhabditis elegans centrosome (the main site of microtubule nucleation in animal cells). SPD-2 localized to the centrioles (of which there are two per centrosome) and accumulated in the pericentriolar material (PCM) during mitosis. This pattern coincided with that of SPD-5, which was shown to be required for SPD-2 accumulation and SPD-2-mediated PCM recruitment. SPD-5, however, was dispensable for the role of SPD-2 in centriole duplication.

Gene transcription

Genome-wide localization of the nuclear transport machinery couples transcriptional status and nuclear organization. Casolari, J. M. et al. Cell 117, 427–439 (2004)

The authors found that, in budding yeast, most nuclear transport factors and nuclear-pore-complex (NPC)-associated proteins bound preferentially to transcriptionally active genes, the majority of which contain sites that bind the transcriptional regulator Rap1. By contrast, the Ran guanine-nucleotide exchange factor Prp20 bound inactive genes. Transcriptional activation caused genes to relocate to the NPC and dissociate from Prp20.

Techniques

Homogeneous detection of unamplified genomic DNA sequences based on colorimetric scatter of gold nanoparticle probes. Storhoff, J. J. et al. Nature Biotech. 30 May 2004 (doi:10.1038/nbt977)

Storhoff et al. described a rapid colorimetric method that detects zeptomole quantities of nucleic acids without the need for target amplification. Gold-particle-labelled DNA probes recognize their target in solution and their nanoparticle scatter is detected by spotting the solution onto a glass microscope slide and exciting it with white light in the plane of the slide. Complexed probes scatter yellow or orange light, whereas free probes scatter green light.

Morphogenesis

Myosin-dependent junction remodelling controls planar cell intercalation and axis elongation. Bertet, C., Sulak, L. & Lecuit, T. Nature 429, 667–671 (2004)

A simple mechanism that enables cells to intercalate in the plane of the epithelium during germ-band elongation in Drosophila melanogaster, despite the presence of adherens cell–cell junctions, is presented. The authors found that myosin II localized in a planar polarized manner at cell–cell junctions, and that this enabled the junctions to disassemble and be remodelled, and cells to intercalate.