Affinity purification to find Arabidopsis TSN1 and TSN2 interacting proteins

As the first step towards a better understanding of the regulation and molecular function of SGs and PBs in plants, we performed affinity purification and mass spectrometry of proteins constituting these mRNP complexes in Arabidopsis. Since TSN has been ascribed a scaffolding role in recruiting other proteins to the stress-induced cytoplasmic mRNP foci, we used two Arabidopsis TSN homologs, TSN1 and TSN2, as baits to purify plant mRNP complex-associated proteins. Our experiments revealed that direct homologs of key components of yeast and animal SGs and PBs are bound to TSN in plants. Interestingly, we also found a group of TSN-interacting proteins that appear to be novel or plant-specific components of mRNP complexes.