An update on the Golgi staining technique improving cerebellar cell type specificity.

The detailed morphological characterization of single cells was a major breakthrough in neuroscience during the turn of the twentieth century, enabling Ramon y Cajal to postulate the neuron doctrine. Even after 150 years, single cell analysis is an intriguing goal, newly motivated by the finding that autism might be caused by intricate and discreet changes in cerebellar morphology. Besides new single labelling technologies, the Golgi staining technique is still in use due to its whole cell labelling characteristics, its superior contrast performance over other methods and its apparent randomness of staining cells within a whole tissue block. However, the specificity and whole cell labelling of Golgi staining are also disputed controversially, and the method still has a poor reputation for being time consuming and needing high expenditures. We demonstrate here, how a classical Golgi technique can be adapted for staining different cerebellar cell types using a time-saving and efficient protocol, enabling the identification of the detailed morphological characteristics of single cells.

Cellular distribution of metastasis suppressor 1 and the shape of cell bodies are temporarily altered in Engrailed-2 overexpressing cerebellar Purkinje cells.

Metastasis suppressor 1 (MTSS1, BEG4, MIM) is well described for its function as a metastasis suppressor gene and is expressed in a variety of tissues. However, only little is known about its expression in the central nervous system (CNS), and functions within the CNS have not been addressed so far. Here, we show that MTSS1 was expressed in postmitotic neurons of the cerebellar cortex. Within Purkinje cells, higher amounts of MTSS1 were temporarily localized in the axonal somatic compartment than in the dendritic compartment. In L7En-2 transgenic mice, in which the segment-polarity gene and regulator of neuronal maturation Engrailed-2 is overexpressed specifically in cerebellar Purkinje cells, MTSS1 was homogenously distributed within Purkinje cell somata throughout development. In parallel to the altered distribution of MTSS1 in L7En-2 Purkinje cells, L7En-2 Purkinje cell somata were distorted and in some cells invaginations of the plasma membrane were observed. These invaginations were only found in L7En-2 neurons, and displayed multiple synapses which could not be seen at the smooth surface of wildtype Purkinje cell somata. Current knowledge about MTSS1 function in vitro and the correlation between MTSS1 localization and the occurrence of membrane alterations in L7En-2 Purkinje cells described here suggest that MTSS1 might be involved in shaping neuronal membranes in vivo.