Pathogenesis Study Based on Single-Cell Sequencing Analysis Reveals the Essential Role of m6A Reader YTHDF1 in Retinal Visual Function via Regulating TULP1 and DHX38 Translation

N6-methyladenosine (m6A) modification of mRNA is an important type of posttranscriptional modification and essential in regulation of mRNA metabolism and various neuronal function. The m6A reader YTHDF1 was reported to enhance translational efficiency of m6A-modifed mRNAs in the brain and be essential for learning and memory. However, the role of YTHDF1 in mature retina remains elusive. Herein, we reported a novel role of Ythdf1 in the maintenance of retinal function using genetic knockout model. Loss of Ythdf1 led to impaired scotopic ERG responses and progressive retinal degeneration. Subsequent detailed examination of rod photoreceptors verified significant degenerative features but no ciliary deficit. Single-cell RNA-seq analysis revealed comprehensive molecular alterations of each retinal cell types in Ythdf1 absent retinas. Combined analysis with methylated RNA immunoprecipitation (Me-RIP) sequencing and RIP-sequencing identified two inheritable retinal degeneration disease associated gene homologues Tulp1 and Dhx38 as the regulating targets of YTHDF1 in the retina. Specifically, YTHDF1 recognized and bound m6A-modified Tulp1 and Dhx38 mRNA at coding sequence (CDS), which enhances their translation efficiency, without affecting mRNA levels. Collectively, our finding highlights the importance of YTHDF1 in the maintenance of visual function and a novel regulating mechanism of m6A reader protein in retinal degeneration, pinpointing potential targets for therapeutical development of severe retinopathy.