The construction of cerebral cortex begins with the formation of radial glia. Once formed, polarized radial glial cells divide either symmetrically or asymmetrically to balance appropriate production of progenitor cells and neurons. Upon birth, neurons use the processes of radial glia as scaffolding for oriented migration. Radial glia thus provide an instructive structural matrix to coordinate the generation and placement of distinct groups of cortical neurons in the developing cerebral cortex. Here we show that Arl13b, a cilia-specific small GTPase mutated in Joubert syndrome patients, is critical for the initial formation of the polarized radial progenitor scaffold. Through developmental stage-specific deletion of Arl13b in mouse cortical progenitors, we found that early neuroepithelial deletion of ciliary Arl13b leads to a reversal in the apical-basal polarity of radial progenitors and aberrant neuronal placement. Arl13b modulates ciliary signaling necessary for radial glial polarity. Our findings demonstrate that Arl13b signaling in primary cilia is important for the initial formation of a polarized radial glial scaffold and suggest that disruption of this process may contribute to aberrant neurodevelopment and brain abnormalities in Joubert syndrome-related ciliopathies.

Of the numerous animal models available for proteomic studies only a small number have been successfully used in understanding human biology. To date, rodents have been widely employed in proteomic and genomic studies but often these models do not truly mimic the relevant human conditions. On the other hand, the pig shows similarity in size, shape and physiology to human and has been used as a major mammalian model for many studies concerning xenotransplantation, cardiovascular diseases, blood dynamics, nutrition, general metabolic functions, digestive-related disorders, respiratory diseases, diabetes, kidney and bladder diseases, organ-specific toxicity, dermatology and neurological sequelae. With the substantially improved knowledge of the structure and function of the pig genome in the last two decades it has been found that this animal shares a high sequence and chromosomal structure homology with humans. Nevertheless, in comparison to other available model organisms, very little work has been devoted to pig proteomics until recently. Keeping this in mind, the present review will highlight some of the advantages and disadvantages of pig as a model system for proteomic studies.

Various CBB-based methods for staining proteins separated by 2-D gel electrophoresis were compared with regard to sensitivity and resolution. A modified Kang's CBB staining protocol, which we have modified, includes phosphoric acid in a concentration of 8% instead of the original 2%. This proved to be the best approach. Protein amounts as low as 2 ng and approximately 2300 spots in the gel can be detected by employing this protocol. The modified procedure takes less time to carry out. Moreover, this practice is more sensitive and resolves more protein spots than most protocols reported to date and is compatible with subsequent mass spectrometric analysis.

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Benzo[a]pyrene (BaP), a five-ring polycyclic aromatic hydrocarbon, is a well-recognized environmental pollutant. Coal-processing waste products, petroleum sludge, asphalt, creosote, and tobacco smoke, all contain high levels of BaP. Exposure to BaP elicits many adverse biological effects, including tumor formation, immunosuppression, teratogenicity, and hormonal effects. In addition to the genetic damage caused by BaP exposure, several studies have indicated the disruption of protein-protein signaling pathways. However, contrary to the large number of studies on BaP-induced DNA damage, only few data have been gathered on its effects at the protein level. This review highlights all proteomic studies to date used for assessing the toxicity of BaP and its metabolites in various organ systems. It will also give an overview on the role proteomics may play to elucidate the mechanisms underlying BaP toxicity.