Part of Xenopus translin is localized in the centrosomes during mitosis

During oogenesis, maternal mRNAs are synthesised and stored in a translatio nally dormant form due to the presence of regulatory elements at the 3' unt ranslated regions (3'UTR). In Xenopus oocytes, several studies have describ ed the presence of RNA-binding proteins capable to repress maternal-mRNA tr anslation. The testis-brain RNA-binding protein (TB-RBP/Translin) is a sing le-stranded DNA- and RNA-binding protein which can bind the 3' UTR regions (Y and H elements) of stored mRNAs and can suppress in vitro translation of the mRNAs that contain these sequences. Here we report the cloning of the Xenopus homologue of the TB-RBP/Translin protein (X-translin) as well as it s expression, its localisation, and its biochemical association with the pr otein named Translin associated factor X (Trax) in Xenopus oocytes. The fac t that this protein is highly present in the cytoplasm from stage VI oocyte s until 48 h embryos and that it has been described as capable to inhibit p aternal mRNA translation, indicates that it could play an important role in maternal mRNA translation control during Xenopus oogenesis and embryogenes is. Moreover, we investigated X-translin localisation during cell cycle in XTC cells. In interphase, although a weak and diffuse nuclear staining was observed, X-translin was mostly present in the cytoplasm where it exhibited a prominent granular staining. Interestingly, part of X-translin underwent a remarkable redistribution throughout mitosis and associated with centros omes, which may suggest a new unknown role for this protein in cell cycle. (C) 2000 Academic Press.