RER and protamine-type proteins during Chara tomentosa L. spermiogenesis

Abstract

In Chara tomentosa during mid spermiogenesis (phases V, VI, VII) when the amount of nuclear protamine-type proteins increases, while the amount of histones decreases, in connection with chromatin remodelling, an extensive RER system filled with dark, fine-granular substance is observed. The intermembranous space of the nuclear envelope is filled with a homogenous substance which looks similar. The most extensive ER system can be observed in phase V, which is at the beginning of nuclear protein exchange. The results presented in this paper correspond with the earlier suggestion based on Chara vulgaris spermioge nesis studies, that ER takes part in a protamine-type protein synthesis, which enter a nucleus by endocytosis, through an inner nuclear envelope membrane.