Acts as a transcriptional activator which regulates the expression of several rod-specific genes, including RHO and PDE6B. Functions also as a transcriptional coactivator, stimulating transcription mediated by the transcription factor CRX and NR2E3. Binds in a sequence-specific manner to the rhodopsin promoter. Interacts with FIZ1; this interaction represses transactivation. Interacts (via the leucine-zipper domain) with CRX. Expressed in the retina (at protein level) (PubMed:11477108). The minimal transactivation domain (MTD) is conserved across the MAF family, it may activate transcription by recruiting TBP and associated factors at the promoters of target genes. Disumoylated at Lys-20. Sumoylation modulates the transcriptional activity of NRL on RHO and NR2E3 promoters, and is required for normal rod differentiation. Phosphorylated. Photoreceptor precursors in retina produce only cones that primarily express S-opsin. Belongs to the bZIP family.