RT-PCR of Cln3 mRNA in wild-type and homozygous CbCln3Δex7/8 cells Cln3 Exon1-forward, Exon 15-reverse RT-PCR products are shown, from total wild-type (+/+) or homozygous mutant (Δex7/8/Δex7/8) brain and cell line RNA. Brain and cell line RT-PCR reaction products had identical band patterns on ethidium-bromide stained agarose gels. Wild-type RT-PCR product was a single ~1.6 kb band and mutant products were ~1.6, ~1.5, ~1.4, ~1.35, and ~1.3 kb, representing multiple mutant splice variants.