A 74-bp promoter of the Tnp2 gene confers testis- and spermatid-specific expression in transgenic mice

During the final stages of spermatogenesis, round spermatids undergo severa l morphological, biochemical, and physiological modifications which result in the formation of mature spermatozoa. One of these is the nuclear condens ation, achieved by the replacement of somatic-type and testis-specific hist ones by transition proteins and protamines leading to cessation of transcri ption several days before the completion of spermiogenesis. Therefore, a st rict temporal and stage-specific gene expression is necessary for the corre ct differentiation of round spermatids into mature spermatozoa. In this stu dy, the 5' regulatory region of rat Tnp2 gene was investigated by primer ex tension analysis and transgenic mice study. Primer extension analysis revea led a transcription start site which lies 70 bp upstream or the translation start codon. By transgenic mice studies, we demonstrated that a 147-bp 5' untranslated region corresponding to the region -74 to +73 is sufficient to confer testis- and spermatid-specific expression of rat Tnp2 gene. (C) 200 1 Elsevier Science.