Characterization of a cDNA containing trinucleotide repeat sequences that is highly enriched in spermatogenic cells.

Trinucleotide repeat sequences have become of great interest due to their association with specific genetic disorders. Here we report the identification of a cDNA containing opa trinucleotide repeats from mouse testis, termed t-OPA. The opa repeat is contained within the longest open reading frame within the cDNA. Northern analysis demonstrated that four distinct t-OPA transcripts (1.6, 2.5, 3.6, 4.0 kilobases) are preferentially expressed in mouse and rat testis, with low expression in the pituitary, brain, and adrenal gland. Further, t-OPA RNAs were highly abundant in both pachytene spermatocytes and round spermatids and decreased in cytoplasts. Polysome profile analysis indicated that t-OPA mRNAs are translated in mouse testis with efficiencies similar to other transcripts expressed in late meiotic/early post-meiotic spermatogenic cells. These findings thus suggest a role for cell-specific mRNAs containing opa repeats during mouse spermatogenesis.