In a paper published online in advance this week in Science, investigators in Switzerland report on how transcriptional bursts "generate gene-specific temporal patterns of mRNA synthesis in mammalian cells." In generating a variety of gene-trap and transgenic cell lines in which an unstable mRNA expressed a luciferase protein, the team recorded on/off transcriptional switching rates by recording bioluminescence; the researchers then used mathematical modeling to show that "bursting kinetics are highly gene-specific."
In a letter appearing in this week's issue, investigators at several institutions across the US and in the UK announce the launch of the "i5k initiative to sequence the genomes of 5,000 species of insect and other arthropods during the next five years." Among other things, the investigators aim to sequence and analyze the genomes of "all species know to be important to worldwide agriculture and food safety, medicine, and energy production."
Researchers in France report in this week's Science that in Saccharomyces cerevisiae, the Mediator subunit Med17 directly interacts with the Rpd3 Polymerase II subunit, such that the physical interaction between them is "generally required for transcription of class II genes."
In Science Signaling this week, an international research team presents its "system-wide temporal characterization of the proteome and phosphoproteome of human embryonic stem cell differentiation." In performing quantitative proteomic and phosphoproteomic analyses in parallel on hESCs during 24 hours of differentiation, the team cataloged a total of "6,521 proteins and 23,522 phosphorylation sites, of which almost 50 percent displayed dynamic changes in phosphorylation status."