A testis-specific promoter in the rat vasopressin gene

In the rat testis, the vasopressin gene is transcribed into precursor RNAs that are processed into a number of mature transcripts. One of these transcripts has a structure identical to that of the hypothalamic RNA that encodes the vasopressin prepropeptide, but is present at such low levels that it can only be detected by the polymerase chain reaction. Other vasopressin-like RNAs are derived from differential splicing events that join transcribed sequences between 3 and 9 kilobases upstream of the hypothalamic transcription start site to exons corresponding to II and III of the hypothalamic-type RNA. Here we describe the sequence of a testis-specific promoter and the exon structure of its transcription unit. We show that an in vitro synthesized RNA corresponding to the longer testicular vasopressin gene-derived transcript is not able to act as a template for protein synthesis in two different cell-free lysates. As attempts to localize the vasopressin-gene derived RNAs to particular cell types in the testis by in situ hybridization have consistently failed, we have used indirect methods. Three different procedures were used to effect germ cell depletion in adult male rats. Acute heat treatment of the testis, chronic ingestion of hydroxyurea, and chronic vitamin A deficiency all reduced the level of the aberrant testicular vasopressin-gene derived RNAs, indicating that their expression is closely associated with the integrity of germ cells and ongoing spermatogenesis.