Chromosomal Location and Genomic Structure of the Human Translin-Associated Factor X Gene (TRAX; TSNAX) Revealed by Intergenic Splicing to DISC1, a Gene Disrupted by a Translocation Segregating with Schizophrenia

Abstract

Two candidate genes, DISC1 and DISC2 on chromosome 1, are disrupted by a translocation that segregates with major psychiatric illness. Several DISC1 transcripts contain TRAX (HGMW-approved symbol TSNAX) sequence at the 5′ end. These transcripts initiate at the 5′ end of TRAX and terminate at the final exon of DISC1. Five species of transcript resulting from intergenic splicing have been identified; one encodes a novel TRAX/DISC1 fusion protein. The remaining four transcripts are bicistronic and encode a series of novel truncated isoforms of TRAX and DISC1. Demonstration that the various TRAX/DISC1 transcripts are translated awaits further experimentation. As a consequence of the observation of intergenic splicing, the human TRAX gene has been mapped at least 35 kb proximal to DISC1 and within approximately 150–250 kb of the translocation breakpoint at 1q42.1. The TRAX gene consists of six exons with a putative CpG island at the 5′ end. Four major transcripts are produced from this gene, of which the smallest, at 2.7 kb, had previously been identified.