Isolation and characterization of trinucleotide repeat containing partial transcripts in human spinal cord

We report the isolation of 41 partial transcripts containing trinucleotide repeats (TNRs) (CAG/CCG or CAA) from human spinal cord using a polymerase chain reaction-based method. The sequence analysis and database search at the nucleic acid and protein level revealed several classes of TNR-containing partial transcripts (TNRPTs). The TNRPTs included 16 known genes and 10 contained or partially overlapped with 13 expressed sequence tags (ESTs), some of which are known to contain TNRs and others which have previously not been shown to contain these repeats (e.g., clone 54 with homology for the hemeobox protein HOX-AS). A further 15 partial transcripts showed no hemologies in the databases and therefore may be unique. The validity of this approach is supported by the detection of nervous system-specific genes (e.g., glial fibrillary acid protein) and genes known to show trinucleotide expansions in disease (e.g., AAD10 associated with spine cerebellar ataxia type 2), This method provides a simple approach for the isolation of TNRPTs, from which full-length transcripts can be obtained and the discovery of TNR-containing genes may be facilitated, TNRPTs can also be used to study quantitative gene expression at the transcriptional level, to construct TNR-enriched cDNA libraries, and to make larger contigs from ESTs.