d Cln3Δex7/8 knock-in mice, which replicate the common JNCL mutation, express mutant battenin and display JNCL-like pathology. Results To elucidate the consequences of the common JNCL mutation in neuronal cells, we used P4 knock-in mouse cerebella to establish conditionally immortalized CbCln3 wild-type, heterozygous, and homozygous neuronal precursor cell lines, which can be differentiated into MAP-2 and NeuN-positive, neuron-like cells. Homozygous CbCln3Δex7/8 precursor cells express low levels of mutant battenin and, when aged at confluency, accumulate ATPase sub