Our Science

What are microRNAs?

MicroRNAs (miRNAs) are  a recently discovered class of small non-coding RNAs that are negative regulators of gene expression in eukaryotic organisms.  Newly synthesized primary miRNA transcripts (pri-miRNAs) are processed by RNase III like enzyme, Drosha, to generate ~70 to 100 nucleotide (nt) hairpin precursors (pre-miRNAs).  Pre-miRNAs which are further processed by another RNase III like enzyme, yield mature miRNAs, averaging 21-23 nt in length.  miRNAs are incorporated into the RNA interference (RNAi) effector complex, RISC, and target specific messenger RNAs for translational repression or mRNA cleavage. MicroRNAs show distinct expression patterns in different organisms, cell development stages, and disease models. Therefore, miRNAs play an important role in regulating gene expression.

Mira Dx is focused on the miRNA-gene interaction. In particular polymorphisms that disrupt the binding of miRNAs to the 3'UTR region of genes have a direct effect on the regulation of the gene. These gain or loss of function mutations when occuring in oncogenes are expected to have a causal effect on the cancer. Since the mutations are germ line the tests are done in blood or saliva rather than tumor tissue, makeing sample access easy.