The mammals possess two genes encoding for Staufen1 (Stau1) and Staufen2 (Stau2), double-stranded RNA binding proteins. Three Stau2 isoforms with molecular weights of 62, 59 and 52 kDa are identified. Stau2 is mainly expressed in nervous system, whereas Stau1 is expressed more ubiquitously. The Staufen proteins are localized in the somatodendritic domain of neurons and play important role in dendritic mRNA targeting. Stau2 was shown to shuttle between the nucleus and the cytoplasm. In order to identify mRNA targets of Staufen proteins, mRNP Immunoprecipitation (RIP) technology was employed and identified distinct but overlapping subset of cellular mRNAs associated with Stau1 and Stau2-containing ribonucleoprotein complexes.
Posttranscriptional regulation of gene expression is a ribonucleoprotein-driven process, which involves RNA binding proteins (RBPs) and non-coding RNAs that affect splicing, nuclear export, subcellular localization, mRNA decay and translation. The RNP Immunoprecipitation-Chip (RIP-Chip), RIP-Seq and RIP-RTPCR allow the identification of multiple RNA targets of RBPs globally and within the context of a cell extract. Antibodies specific to the RNA binding protein of interest are used to co-immunoprecipitate the RNA binding protein and the associated subset of mRNAs. The mRNA content is interrogated using standard microarray or sequencing technology. RIP-Certified Antibody is validated for use in RNP Immunoprecipitation (RIP) in conjunction with the RIP-Assay Kit distributed from MBL. Its ability to immunoprecipitate mRNAs and RBPs complex was confirmed by quantitative and qualitative analysis on NanoDrop, Bioanalyzer and RT-PCR or microarray.