NXNL1 and retinal degeneration: Other mutation-independent strategies tested in mouse models of retinal degeneration aimed to promote photoreceptor cell survival, as a CRISPR-mediated knockdown of the key transcription factor Neural Retina Leucine zipper (Nrl), or a viral-mediated expression of the rod-derived cone viability factor (RdCVF) (32, 33).