Due to the shared hindbrain phenotype observed in zebrafish and the established role of the TSEN/CLP1 complex in tRNA splicing, we pursued defective tRNA splicing as a potential disease mechanism. In order to study the relative expression of the known 32 intron-containing tRNA isoforms (i.e. genes), following reverse transcription (RT) of total RNA, we generated isoform-specific pre-tRNA primers to each, utilizing the unique intronic sequence for the reverse primer (Figure 4A). Excluding those that failed PCR or where expression was undetectable, using RT-PCR we profiled the expression of the remaining 15 in human cortex, iNeurons, and fibroblasts (Figure S4A). Expression in brain more closely mirrored expression in iNeurons than fibroblasts, supporting the use of iNeurons for these experiments.
