Biology Forums - Study Force

As our knowledge of the transcriptome space has expanded, it has become increasingly clear that numerous miRNA-binding sites exist on a wide variety of RNA transcripts, leading to the hypothesis that all RNA transcripts that contain miRNA-binding sites can communicate with and regulate each other by competing specifically for shared miRNAs, thus acting as competing endogenous RNAs (ceRNAs)

MicroRNAs (miRNA) are an abundant class of small, non-coding RNAs (∼22 nt long), which negatively regulate gene expression at the level of messenger RNAs (mRNAs) stability and translation inhibition (1). Dysregulation of miRNA activity has been shown to play an important role in tumor initiation and progression (2–4). In addition to the conventional miRNA/mRNA function, recent studies have shown that the interaction of the miRNA seed region with mRNA is not unidirectional, but that the pool of mRNAs can crosstalk through their ability to compete for miRNA binding (5,6). These competitive endogenous RNAs (ceRNAs) act as molecular sponges for a miRNA through their miRNA binding sites (also referred to as miRNA response elements, MRE), thereby de-repressing all target genes of the respective miRNA. Yet few such modulators of miRNA activity have been characterized and both the extent and relevance of their role in cancers are poorly understood.