G-Rich RNA Sequence Binding Factor 1 (GRSF1)

The GRSF1 cDNA has a long 3-prime untranslated region containing 2 polyadenylation signals. The open reading frame encodes a deduced 424-amino acid protein with a calculated molecular mass of 48 kD. The protein contains 3 RNA recognition motifs and 2 auxiliary domains. Northern blot analysis indicated 2 predominant mRNAs of 1.7 and 2.8 kb. Indirect immunofluorescence microscopy with anti-GRSF1 monoclonal antibody and in vivo UV crosslinking experiments suggested that GRSF1 is a cytosolic poly(A)+ mRNA-binding protein.

Grsf1 upregulated Gpx4 UTR-dependent reporter gene expression, recruited mitochondrial Gpx4 mRNA to translationally active polysomes, and coimmunoprecipitated with Gpx4 mRNA.