Linear isoforms of the long noncoding RNA CDKN2B-AS1 regulate the c-myc-enhancer binding factor RBMS1.

Variants in the long noncoding RNA (lncRNA) gene CDKN2B-AS1 (CDKN2B antisense RNA 1; ANRIL) are genome-wide associated with type 2 diabetes (T2D), atherosclerosis, and several forms of cancer. However, it is currently not understood how CDKN2B-AS1 transcripts translate into diabetes. We previously demonstrated trans-regulation of the proximal polyadenylated transcripts on several genes with functions in glucose and lipid metabolism. However, information on specific genes that are regulated at physiological concentrations by the distal polyadenylated CDKN2B-AS1 transcripts is lacking. To identify target genes of CDKN2B-AS1 trans-regulation, we designed inducible short hairpin RNA constructs and integrated them into the genome of T-Rex HEK293 cells. Changes of gene expression after induction were determined at defined time points by genome-wide mRNA expression analysis. We confirmed downregulation of RBMS1, located on chromosome 2 (RNA-binding motif, single-stranded interacting protein 1) at the transcript and protein level in stable-transfected, inducible HeLa cells, and demonstrated that the effect was independent of the cell type, known cis-regulatory effects, and regulation of the proximal polyadenylated CDKN2B-AS1 isoforms. Direct binding of CDKN2B-AS1 transcripts to RBMS1 was shown by RNA immunoprecipitation. RBMS1 encodes a cell cycle suppressor. We conclude that the distal and proximal polyadenylated CDKN2B-AS1 transcripts have separate functions in gene regulation, which are independent of the circular CDKN2B-AS1 isoforms and of the genes CDKN2A/2B.