Transcribed Ultraconserved Regions in Cancer

Abstract

Transcribed ultraconserved regions are putative lncRNA molecules that are transcribed from DNA that is 100% conserved in human, mouse, and rat genomes. This is notable, as lncRNAs are typically poorly conserved. TUCRs remain very understudied in many diseases, including cancer. In this review, we summarize the current literature on TUCRs in cancer with respect to expression deregulation, functional roles, mechanisms of action, and clinical perspectives.

Keywords: TUCR; cancer; long non-coding RNA; ultraconserved.

Figure 1

TUCRs represent highly conserved lncRNAs. LncRNAs are typically poorly conserved, while TUCRs are 100% conserved in human, mouse, and rat genomes. The TUCR uc.8 ((A), green box) is highly conserved ((A), red box) compared to the lncRNA LINC02079 ((B), green box), which is more poorly conserved ((B), red box). Nucleotide conservation is highlighted for uc.8 and LINC02079 (C) and quantified (D).

Figure 2

TUCRs are found on all number chromosomes and the X chromosome. TUCR locations are marked with a black vertical line showing their relative position on the chromosome. bp = base pair.

Figure 3

TUCRs can be intragenic or intergenic. Intragenic TUCRs can be found within the exon of their “host gene” (A), an intron (B), or straddling splice sites as exonic/intronic (C). The remainder exist outside of annotated DNA/RNA and are considered to be intergenic (D).