In a new study appearing in PNAS this week, Brandeis Molecular and Cell Biology graduate student Houra Merrikh and co-workers from the Lovett lab identified the E.coli gene iraD as a regulator of the response to oxidative DNA damage in exponentially growing bacteria. Interestingly, the mechanism seems to involve the alternative RNA polymerase sigma factor RpoS, previously characterized as a regulator of expression during the “stationary phase”. Merrikh et al. argue that this response works in parallel with the previously characterized SOS response in protecting growing bacteria from DNA damage.
Microscopy (2): studying molecular motors
January 4, 2009 By
An article in Cell by recent Molecular and Cell Biology Ph.D. graduate Susan Tran and coworkers demonstrates the power of single particle microscopy in combination with Drosophila genetics in studying molecular motors. Studying lipid droplet movement in embryos, they show that multiple motors are attached to droplets in vivo. Surprisingly, having multiple motors per droplet in vivo doesn’t result in higher velocities or distances traveled.
Cell cycle checkpoint from the stringent response
December 17, 2008 By
E.coli cells exiting the stringent response
The stringent response in E.coli is a response to nutrient (typically amino acid) starvation and is characterized by the accumulation of the small molecular regulator ppGpp, and a global response in transcriptional regulation. In a new paper in PLoS Genetics, Daniel Ferullo and Susan Lovett examine chromosome segregation during the stringent respons and discuss what appears to be a novel G1-like cell cycle checkpoint in bacteria that occurs as the result.
