microRNA co-target network in human : implications of clustered microRNAs in biological pathways and genetic diseases

The diversity and abundance of micro RNA (miRNA) targets offer an enormous level of combinatorial possibilities and suggest that miRNAs and their targets appear to form a complex regulatory network. Analysis of combinatorial network constructed  from the pair wise co-targets of miRNAs reveals that only about 50% miRNAs  provide all essential regulation. We argue that these relevant set of miRNAs form several small clusters, and show that these clusters are building blocks of biological functions. The miRNAs which deregulate the genes involved in several diseases (obtained from published experimental studies) are found to be cluster specific. We propose that the genes are better regulated by co-targeting of clusters of miRNAs, compared to single ones.