As an alternative approach to genetic manipulation of mice, considerable effort has been devoted to transduce Purkinje cells using various types of viral vectors (Hirai, 2008). However,

each vector has limitations with respect to the efficiency, specificity, toxicity and length of the insert. For example, AAV vectors have strict limitation Metformin mouse of the length of insert up to 5 kb including a promoter (Wu et al., 2010). The limit for the length of insert for lentiviral vectors is up to 8 kb (Hirai, 2008). In addition, 30% of cells infected by one of the best Purkinje cell-specific lentiviral vectors were non-Purkinje cells, such as Bergmann glia, stellate and basket cells (Takayama et al., 2008). The Sindbis virus enables the rapid production of high levels of recombinant protein in Purkinje cells; however, its use is limited by the cytotoxicity to Purkinje cells (Kohda et al., 2007). The adenovirus vectors preferentially infect Bergmann glia rather than Purkinje cells in vivo (Hashimoto et al., 1996; Terashima et al., 1997; Kakegawa et al., 2011). Although injection of adenovirus into the fourth ventricle of embryonic mice could efficiently deliver

genes into cerebellar progenitors (Hashimoto & Mikoshiba, 2003), cell-type specificity was not examined at the PI3K inhibitor cellular level. It also remains unclear whether Purkinje cells infected with adenovirus in utero maintain normal physiological properties, such as synaptic plasticity. Therefore, we believe oxyclozanide that the new IUE protocol can complement the current transgenic and viral vector approaches; major advantages of IUE

include simplicity, high specificity to Purkinje cells, low toxicity, and high efficiency to introduce large and multiple genes. A drawback of the current IUE protocol is that although Purkinje cells are always transfected, a small number of neurons, which are probably generated near the rhombic lip during a similar time window, are sometimes transfected as well. Although cell specificity can be easily achieved by using the L7 promoter (Fig. 3), early expression of a transgene is then limited by the L7 promoter activity. Nevertheless, as a method for transferring genes into Purkinje cells, IUE has a better specificity for Purkinje cells than lentivirus vectors (Fig. 1D; Torashima et al., 2006). Another drawback of the IUE method is that it can only introduce genes in a subpopulation of Purkinje cells. This is partly because only the Purkinje cell progenitors that are located at the surface of the fourth ventricle at the time of IUE will be transfected. Similarly, adenovirus vectors injected into the fourth ventricle at E11.5 and E12.5 infect only the subpopulation of Purkinje cell progenitors that were born on the day of each injection (Hashimoto et al., 1996).