In the absence of nElavl proteins, the level of glutamate is severely compromised, and this imbalance is associated with seizures in Elavl3

null mice. Taken together our genome-wide approaches identify in vivo targets and functions of nElavl proteins in regulating brain RNA and excitability. To assess the functional action of Elavl3 on target transcripts, we first generated an Elavl3 null mouse by homologous recombination in ES cells ( Figure 1A). Mice harboring the homologous recombinant cassette made no detectable Elavl3 by either RNA or protein analysis, including western blot and immunofluorescence microscopy ( Figure 1B and data not shown). Elavl3−/− mice were viable and fertile. However, when they were inbred into a C57Bl/6 background, we noted that Elavl3−/− mice were present in new litters at well-below Mendelian ratios Selleckchem BMN673 (∼10% offspring from the mating of two heterozygous parents). Interestingly, when Elavl3−/− mice were outbred into the CD1 strain, Elavl3−/− pups were born at Mendelian ratios, suggesting gene modifiers present in the outbred CD1 strain. We contrasted nElavl immunofluorescence remaining in Elavl3−/− mouse brain with previously characterized Elavl3

expression characterized by in situ hybridization ( Okano and Darnell, 1997). In particular, we had previously noticed that several neuronal types showed nearly exclusive expression of Elavl3 among all nElavl isoforms, including cerebellar Purkinje neurons and hippocampal dentate gyrus (DG) neurons. Immunofluorescence microscopy using a pan-nElavl antibody revealed the absence only of detectable remaining see more nElavl protein in both

Purkinje and DG neurons in the Elavl3−/− brain ( Figures 1D and 1E), consistent with Elavl3 being the sole nElavl protein in these neurons. Given that all nElavl expression was eliminated in Elavl3−/− Purkinje neurons, we decided to analyze cerebellar function in these mice by rotarod assay. This behavioral assay is widely used to evaluate cerebellar dysfunction; however, other explanations to reduced time on rotating rod are potentially possible. Young adult Elavl3−/− mice showed significant defects in this assay (p = 0.001) relative to heterozygous littermates ( Figure 1C). In order to exclude a generalized synaptic dysfunction in these mice, we measured time to tail-twitch on hotplate testing as a measure of sensory function and observed no difference in either genotype, consistent with the observation that Elavl2, 3, and 4 are all robustly expressed in dorsal root ganglia ( Okano and Darnell, 1997). Taken together, these observations suggest that there are subsets of neurons that are particularly vulnerable to the loss of Elavl3, while others are relatively resistant, consistent with the expression patterns of the individual family members and functional redundancy among nElavl proteins.