The MicroRNA Family Both in Normal Development and in Different Diseases: The miR-17-92 Cluster

Figure 2

Structure of the miR-17-92 polycistronic gene. Some miRNA genes are clustered on chromosomes, transcribed by a common promoter to generate a polycistronic transcript, and then processed to produce multiple mature miRNAs. In some miRNA gene clusters each member has a functional additive effect that is more effective than a single miRNA. Members of the miRNA gene cluster can coordinate the regulation of certain processes or play a similar role in the same biological process, ensuring biological activity occurs in a normal and orderly fashion. miR-17-92 encodes a miRNA precursor and produces 7 mature miRNA molecules that belong to 4 miRNA families.