, 2011 and Wu et al., 2009). While light-induced photoactivation has been

in the cell biologists’ toolkit for decades, these methods have required chemical Vorinostat ic50 modification of molecules or proteins, which must then be somehow introduced to the intracellular environment and uncaged with UV light. It is only in recent times that the technique has been combined with the ease of genetically encoded expression and the use of visible light wavelengths, making the experiments very amenable to live neurons in culture or even in vivo. This can be attributed to exploitation of light sensitive domains isolated from plant proteins. These can be used to either allosterically block an active protein from interacting with its effectors (Wu et al., 2009), or to artificially dimerize two targets (Kennedy et al., 2010 and Levskaya et al., CDK inhibitor 2009). In the latter example, artificial interaction can be used to either anchor a target protein to a specific subcellular compartment or to cause an association

between two targets. In both cases, light absorption activates a synthetic signaling cascade that is both reversible and dose dependent. Like CALI, light-induced photoactivation is instantaneous and can be performed at the subcellular level. Overall, this type of manipulation is a better approximation of actual signaling events and an invaluable tool for deducing the true function of a protein in a specific cellular process. Together with the development and deployment of super resolution imaging techniques (Toomre and Bewersdorf, 2010), we might be closer to a better understanding of the full orchestra of the players that power the growth cone. Research in authors′ lab is supported in

part by grants from the National Institutes of Health to J.Q.Z. and a Ruth L. Kirschstein National Research Service Award to E.A.V. “
“The mammalian neocortex is characterized by its stereotyped laminar cytoarchitecture and regional variations in cellular architecture that differentiate cortical areas. As emphasized by Brodmann over a century ago through the creation of cytoarchitectonic cortical maps (Brodmann, 1909), cortical organization is conserved across species, particularly between humans and nonhuman primates (reviewed in Zilles Levetiracetam and Amunts, 2010). Gene expression is increasingly used as an empirical means of differentiating and delineating cortical areas, for example through identification of area-specific gene markers (Takahata et al., 2009) or boundary mapping based on differences in neurotransmitter receptor expression (Zilles et al., 2004). Whole-genome transcriptional profiling has particular potential to elucidate cortical areal specification and specialization through identification of differentially regulated genes and molecular pathways that underlie cytoarchitectural and functional areal identity (Johnson et al., 2009).