Identification of a Long Non-Coding RNA Derived From the Antisense Strand of the Thyroid Hormone Receptor Beta Gene

Background: Long non-coding RNAs (lncRNAs) have various functions. Here, we describe a novel lncRNA which is induced from the antisense strand of the thyroid hormone receptor beta (THRB) gene. Methods: We sequenced RNA from leukocytes and identified a novel lncRNA derived from the antisense strand of the THRB gene. The lncRNA was named THRB antisense RNA 2 (THRB-AS2). Transcriptional regulation by THRB-AS2 was assessed by reporter assays. The putative translation initiation codons of THRB-AS2 were mutated to assess potential THRB-AS2 protein function. Results: THRB-AS2 stimulated the activities of multiple promoters irrespective of thyroid hormone response elements. Thyroid hormone treatment did not affect the function of THRB-AS2. These data suggest that THRB-AS2 is a potential general transcriptional activator and has broad specificity on target genes. Mutations in putative translation initiation codons of THRB-AS2 did not affect function, suggesting that THRB-AS2 acts as an RNA molecule. Conclusions: Although a small number of lncRNAs derived from antisense strand of the THRB gene, such as THRB-AS1, has been already reported, their functions remain largely unknown. To our knowledge, this is the first report of the functions of a lncRNA derived from the antisense strand of the THRB gene.