Identification of Translin and Trax as Components of the GS1 Strand‐Specific DNA Binding Complex Enriched in Brain

• Published in: Journal of neurochemistry Vol. 71; no. 2; pp. 471 - 477
• Main Authors: Taira, Eiichi, Finkenstadt, Patricia M., Baraban, Jay M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.08.1998; Blackwell
• Subjects: Animals; Biochemistry and metabolism; Biological and medical sciences; Brain; Brain Chemistry - physiology; Carrier Proteins - analysis; Carrier Proteins - metabolism; Central nervous system; Cerebellum - chemistry; Cross-Linking Reagents; DNA recombination; DNA, Single-Stranded - metabolism; DNA-Binding Proteins - analysis; DNA-Binding Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation - physiology; Gene Expression Regulation - radiation effects; GS1 binding activity; GS1 protein complex; Leucine Zippers - physiology; Lymphocyte; Lymphocytes; Molecular Sequence Data; mRNA translation; Nuclear Proteins - analysis; Nuclear Proteins - metabolism; Protein Biosynthesis - physiology; Proteins - analysis; Proteins - metabolism; Rats; Recombination, Genetic - physiology; RNA, Messenger - metabolism; Sequence Homology, Amino Acid; Translin; Trax; Ultraviolet Rays; Vertebrates: nervous system and sense organs; Vertebrata; Translation; Mammalia; Rat; Rodentia; Central nervous system; Molecular complex; Single stranded DNA; Lymphocyte; Single strand DNA binding protein; Brain (vertebrata)
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1046/j.1471-4159.1998.71020471.x

: In previous gel‐shift assays, we identified a protein complex, referred to as GS1, that binds in a sequence‐specific manner to single‐stranded DNA and is highly enriched in brain. As an initial step in clarifying the function of this complex, we have undertaken studies aimed at defining its protein components. In particular, we focused on identifying two protein bands that were covalently labeled when the GS1‐DNA complex was subjected to UV irradiation to induce cross‐linking between the radiolabeled probe and GS1 components. By following GS1 binding activity through a series of conventional chromatographic steps, as well as an affinity column based on the DNA oligonucleotide used for gel‐shift assays, we were able to achieve ∼500,000‐fold enrichment of GS1 compared with that in crude cerebellar extracts used as starting material. This highly purified fraction contained both protein bands detected by UV cross‐linking in crude extracts. Sequencing of peptides derived from these proteins led to their identification as Translin and Trax, interacting proteins identified in studies of DNA recombination in lymphocytes. A distinct line of research has provided evidence that a complex containing Translin can bind to specific mRNAs and block their translation. Whether one or both of these proposed functions of the Translin/Trax complex explains the high basal level of GS1 binding activity present in the brain remains to be determined.