The total retinal RNA from healthy human donor eyes that were obtained from the National Disease Research Interchange (Philadelphia, PA, USA) was generously provided by Dr. D. B. Farber (UCLA; Young et al. 2011 (link)). The RNA was DNase treated with Turbo DNA-free (Ambion, Austin, TX, USA) and purified with RNeasy MiniElute Cleanup kit (Qiagen, Valencia, CA, USA). The first-strand cDNA from 5 μgs of the total RNA was reverse transcribed with oligo-dT primer and M-MuLV (NEB, Beverly, MA, USA). Rbpms splicing variants were identified by PCR, with primers specific to Rbpms isoforms and first-strand retinal cDNA used as a template.