Discovery of a novel non-coding RNA, THOR
From an initial large-scale screening for highly conserved long intergenic non-coding RNA with varying evolutionary conservation, lineage expression, and cancer specificity, we discovered and functionally characterized a novel ultraconserved lncRNA, THOR that exhibits expression exclusively in testis and a broad range of human cancers. THOR knockdown and overexpression in multiple cell lines and animal models altered cell or tumor growth supporting an oncogenic role. We discovered a conserved interaction of THOR with IGF2BP1 and showed that THOR contributes to the mRNA stabilization activities of IGF2BP1. Notably, transgenic THOR knockout produced fertilization defects in zebrafish and also conferred a resistance to melanoma onset. Likewise, ectopic expression of human THOR in zebrafish accelerated the onset of melanoma. THOR represents a novel class of functionally important cancer/testis lncRNAs whose structure and function have undergone positive evolutionary selection.