A post-transcriptional operon is a set of monocistronic mRNAs encoding 
functionally related proteins that are co-regulated by a group of RNA-binding 
proteins and/or small non-coding RNAs so that protein expression is coordinated 
at the post-transcriptional level. The post-transcriptional operon model (PTO) 
is used to describe data from an assortment of methods (e.g. RIP-Chip, 
CLIP-Chip, miRNA profiling, ribosome profiling) that globally address the 
functionality of mRNA. Several examples of post-transcriptional operons have 
been documented in the literature and demonstrate the usefulness of the model in 
identifying new participants in cellular pathways as well as in deepening our 
understanding of cellular responses.