Virology

A novel approach for producing lentiviruses that are limited to a single round of infection

The development of lentiviral strains capable of only one round of infection is of great interest to researchers investigating the dynamics and pathogenesis of HIV and SIV. Evans et al. present such an SIV strain, created by mutating the ribosomal frameshifting site between the gag and pol reading frames, observing successful restriction in vitro and in vivo.

Evans, D.T. et al. J. Virol. 78, 11715–11725 (2004).

Microscopy

Serial block-face scanning electron microscopy to reconstruct three-dimensional tissue nanostructure

Block-face imaging offers an effective means for the generation of serial microscopic images. Denk and Horstmann apply this system in the context of environmental scanning electron microscopy, obtaining serial data that enable the high-resolution three-dimensional reconstruction of neural circuits and other nanostructures.

Denk, W. & Horstmann, H. PLoS Biol., published online 19 October 2004.

Cell biology

Mapping the dynamic organization of the nuclear pore complex inside single living cells

About 30 different nucleoporin proteins compose the nuclear pore complex, mediating transport of molecules between cytoplasm and nucleus. Rabut et al. have created and analyzed a series of cell lines expressing many of these proteins as GFP fusions, in an effort to better understand the in vivo dynamics of each different pore-complex component.

Rabut, G. et al. Nat. Cell Biol., 6, 1114–1121 (2004).

Microarrays

Distinct effects on gene expression of chemical and genetic manipulation of the cancer epigenome revealed by a multimodality approach

Gius et al. apply a microarray strategy to characterize the impact on gene expression patterns resulting from different methods of modulating DNA methylation and find that the effects of genetic modification to eliminate DNA methyltransferase expression unexpectedly differ from those induced by drugs altering methylation or histone acetylation.

Gius, D. et al. Cancer Cell 6, 361–371 (2004).

Immunochemistry

Targeted gene alteration in Caenorhabditis elegans by gene conversion

Transposon-based mutagenesis is a popular method for C. elegans genetic studies, but it requires the screening of large numbers of worms, and researchers have little control over the introduced changes. Barrett et al. describe a combined approach using transposons and modified transgenes to efficiently introduce targeted replacements, deletions and insertions in a mutator worm strain.

Barrett, P.L. et al. Nat. Genet. 36, 1231–1237 (2004).