Combinatorial mRNA binding by AUF1 and Argonaute 2 controls decay of selected target mRNAs.

The RNA-binding protein AUF1 binds AU-rich elements in 3'-untranslated regions to regulate mRNA degradation and/or translation. Many of these mRNAs are predicted microRNA targets as well. An emerging theme in post-transcriptional control of gene expression is that RNA-binding proteins and microRNAs co-regulate mRNAs. Recent experiments and bioinformatic analyses suggest this type of co-regulation may be widespread across the transcriptome. Here, we identified mRNA targets of AUF1 from a complex pool of cellular mRNAs and examined a subset of these mRNAs to explore the links between RNA binding and mRNA degradation for both AUF1 and Argonaute 2 (AGO2), which is an essential effector of microRNA-induced gene silencing. Depending on the specific mRNA examined, AUF1 and AGO2 binding is proportional/cooperative, reciprocal/competitive or independent. For most mRNAs in which AUF1 affects their decay rates, mRNA degradation requires AGO2. Thus, AUF1 and AGO2 present mRNA-specific allosteric binding relationships for co-regulation of mRNA degradation.

A birth-to-death view of mRNA from the RNA recognition motif perspective.

RNA binding proteins are a large and varied group of factors that are the driving force behind post-transcriptional gene regulation. By analogy with transcription factors, RNA binding proteins bind to various regions of the mRNAs that they regulate, usually upstream or downstream from the coding region, and modulate one of the five major processes in mRNA metabolism: splicing, polyadenylation, export, translation and decay. The most abundant RNA binding protein domain is called the RNA Recognition Motif (RRM)1. It is probably safe to say that an RRM-containing protein is making some contact with an mRNA throughout its existence. The transcriptional counterpart would likely be the histones, yet the multitude of specific functions that are results of RRM based interactions belies the universality of the motif. This complex and diverse application of a single protein motif was used as the basis to develop an advanced graduate level seminar course in RNA:protein interactions. The course, utilizing a learner-centered empowerment model, was developed to dissect each step in RNA metabolism from the perspective of an RRM containing protein. This provided a framework to discuss the development of specificity for the RRM for each required process.

Using a Mobile Laboratory to Promote College-Level Outreach and Graduate Student Engagement in Precollege STEM Literacy.

This article presents a case study about the impact that our mobile laboratory, the Rutgers Science Explorer bus, has had on the professional development of graduate students and content enrichment for the middle school communities in the state of New Jersey.