Canonical microRNA Matching Differs Greatly Across Groups of G-protein Coupled Receptor mRNAs

Background: Heptahelical G protein coupled receptors (GPCRs) support numerous sensory and metabolic functions and differ considerably in levels of expression. GPCR protein levels should link to regulation of GPCR mRNAs by microRNAs (miRs), which might significantly depend on numbers, size and GC content of the canonical antisense matches in mRNAs. These parameters of GPCR mRNAs have not been studied in detail. Methods: Canonical matching profiles of human GPCR mRNAs and miRs were examined using segments of 7-15 nucleotides in windows shifted by one position over the entire microRNA sequence. Results: Human GPCRs mRNAs within larger function-related groups have a quite homogenous matching with miRs. Both the GC content and the melting temperature (and hence also the binding energy) are appreciably higher in 5'utr compared to 3'utr matches of the same length. Increase in the GC content correlates significantly with length in the ubiquitous matches of 7-12 nucleotides. However, several GPCR groups strongly differ in overall match numbers and density. The untranslated regions of sensory receptor mRNAs, especially the olfactory and Taste-2 mRNAs, have the lowest match numbers and density and the fewest miR partners. The glucagon and frizzled families show the highest canonical matching. Conclusion: Partnership of GPCR mRNAs and miRs could significantly relate to the type of function of the receptor proteins, with mRNAs of the sensory receptors having the lowest and those of metabotropic GPCRs the highest targeting. This could be of interest regarding GPCR regulation by exogenous miRs.