Accepted_test

In this study, we analyzed the expression of SLC4A11 gene transcripts in human corneal endothelium. The expression level of different SLC4A11 isoforms was assessed using two sets of corneal endothelial transcriptomes, each set including a group of healthy patients and patients with Fuchs' corneal endothelial dystrophy (FECD). The results showed that the highest expression was observed for isoforms 3 and 6, and the non-coding isoform, NR_174471, was also highly expressed. Meanwhile, the expression of isoform 2, the most abundant isoform in the corneal endothelium according to literature data, was estimated to be very low. The bioinformatic results were further validated using the 5'RACE method and subsequent sequencing of the resulting amplicon sets on the Illumina MiSeq platform. For one of the samples, we performed preliminary Sanger sequencing of the most abundant 5'RACE products, which were the 5'-end regions of isoforms 6 and NR_174471. Preliminary analysis of the sequencing results of one of the samples on Illumina MiSeq showed that the most abundant isoform was isoform 6, some of the reads also corresponded to the 5' region of isoform 3, reads corresponding to isoform 2 were almost absent.
Thus, we obtained evidence for the predominant expression of SLC4A11 isoforms 3 and 6 in the corneal endothelium and a low representation of isoform 2. These data will not only help to clarify the information on the protein isoforms of SLC4A11 predominantly produced in the corneal endothelium, but also to characterise the function of the SLC4A11 promoter region in this tissue.