Science's special section this week looks at the cell's nucleus. A news story chronicles the search for the spindle matrix, a still-hypothetical cellular structure that may underlie the spindle. Kristen Johansen and Jørgen Johansen have uncovered four matrix protein candidates and Yixian Zheng has isolated RanGTPase which triggers spindle formation in frog eggs. One review paper discusses nuclear dynamics and how fluorescence microscopy and proteomics are aiding in studying nuclear structure and function. Two other reviews report on the nuclear envelope -- its role in cytoskeleton and nuclear architecture and in how the transportation of molecules across the envelope is regulated.
Edward Rubin's lab studied 246,045 genes from 79 prokaryotic genomes that tried to move horizontally into E. coli and identified 642 genes that were, repeatedly, not able to transfer. This, the researchers say shows that there are universal gene-transfer barriers. The researchers hypothesize that many of these genes could not undergo horizontal gene transfer because the genes were toxic to E. coli.
Scientists led by Christopher Schofield took a bioinformatics approach to studying the fat mass and obesity associated gene FTO, which is associated with increased BMI in humans. Through their analysis, they found that FTO shares motifs with Fe(II)- and 2-oxoglutarate-dependent oxygenases and, in recombinant mice, FTO catalyzes Fe(II)- and 2OG-dependent demethylation of single-stranded DNA. In wild-type mice FTO mRNA is most concentrated in the brain, especially where energy balance is controlled.