Partial characterization of a new basic nuclear protein from rat testis elongated spermatids.

A basic protein designated TP2 has been isolated from rat testis elongated spermatids. This new protein contains basic and acidic amino acids in relative amounts similar to those in histone F2al but is unusually rich in serine and proline. Techniques which were developed for preparing relatively homogeneous populations of spermatid nuclei were used to demonstrate that TP2 is most abundant and most actively synthesized in spermatids representing steps 12 through 15 of spermiogenesis.