Evaluation of the mirn23a Cluster through an iTRAQ-based Quantitative Proteomic Approach

MicroRNAs (miRNAs) are post-transcriptional
regulators of gene
expression that are implicated in a number of disease states. MiRNAs
can exist as individual entities or may be clustered and transcribed
as a single polycistron. The mirn23a cluster consists of three miRNAs:
miR-23a, miR-24-2, and miR-27a. Although these miRNAs are transcribed
together, they often exist at varying levels in the cell. Despite
the fact that the mirn23a cluster is known to play a role in a number
of diseases and developmental processes, few direct targets have been
identified. In this study, we examined the effects of miR-23a, miR-24-2,
miR-27a, or the mirn23a cluster overexpression on the proteome of
70Z/3 pre-B lymphoblast cells. Quantitative mass
spectrometry using isobaric tags for relative and absolute quantification
(iTRAQ) allowed for the global profiling of cell lines after miRNA
overexpression. We identified a number of targets of each miRNA that
contained predicted miRNA seed sequences and are likely direct targets.
In addition, we discovered a cohort of shared miRNA targets and cluster
targets, demonstrating the importance of studying miRNA clusters in
their entirety.