●Monitoring p53's pulse. Tyson, J. J. Nature Genetics February (2004). Levels of p53 increase in response to DNA damage. This News and Views article discusses a paper showing that rather than a simple correlation between levels of DNA damage and levels of p53, p53 is produced in pulses, with higher levels of damage generating more pulses.

●Nucleocytoplasmic shuttling of signal transducers. Xu, L. & Massagué, J. Nature Reviews Molecular Cell Biology March (2004)

●The art and design of genetic screens: mammalian culture cells. Grimm, S. Nature Reviews Genetics March (2004)

●RASSF1A, the new guardian of mitosis. Máthé, E. Nature Genetics February (2004) This News and Views article highlights a new study showing that the product of the RASSF1A tumour-suppressor gene interacts with CDC20 to inhibit the anaphase-promoting complex and regulate mitosis.

●Expression profiling — best practices for data generation and interpretation in clinical trials. The Tumor Analysis Best Practices Working Group.Nature Reviews Genetics March (2004)

●Modifying NEMO. Hay, R. T. Nature Cell Biology February (2004) Activation of the NF-κB transcription factor in response to genotoxic stress requires its release from its inhibitor, IκBα. This News and Views article describes a recent study showing that this process requires the modification of NEMO (IKKγ) by SUMO and ubiquitin.

●First dose of potential new medicines to humans: how animals help. Greaves, P., Williams, A. & Eve, M. Nature Reviews Drug Discovery March (2004) This review discusses how pre-clinical trials in animals can contribute to the safer testing of new drugs in humans.

●Nature Reviews Microarrays collection. This web focus will be available free online for 6 months from March 2004.www.nature.com/reviews/focus/microarrays