Staufen forms distinct RNPs in Normal and Stress Conditions

THOMAS, M.G.;; LOSCHI M;; KINDLER, S.; BOCCACCIO, GRACIELA

Iguazú, Misiiones, Argentina

Congreso; XL Reunión SAIB; 2004

The double-stranded RNA-binding protein Staufen is a quite ubiquitous RNA granule-forming factor required for mRNA localization in different organisms. We have recently found that in rodent oligodendrocytes Staufen 1 and Staufen 2 are present in two independent sets of RNA granules located at the distal myelinating processes and associated to cytoskeleton and polysomes (Thomas et al, 2004). Under oxidative stress, both homologues are recruited into stress granules (SGs). SGs are stress-induced organelles that contain transiently silenced messengers and have perinuclear localization. Staufen SGs also include Poly(A)-binding protein (PABP), the RNA-binding proteins HuR and TIAR, and small but not large ribosomal subunits. Our results indicate that Staufen 1 and Staufen 2 are novel and ubiquitous SG components and suggest that Staufen RNPs are involved in repositioning of most polysomal mRNAs during the stress response. Currently, we are trying to isolate Staufen SGs from rat oligodendrocytes and transfected cell lines via cell fractionation and purification strategies based on immunoprecipitation and Staufen-tagged constructs. To gain insight into Staufen SG function we will study the protein and RNA composition of the isolated SG by mass spectrometry and microarray analysis respectively.