Behaviour of microchromosome-associated satellite DNA in the banded krait,Bungarus fasciatus (Ophidia, Elapidae)

Abstract

Banded krait (Bungarus fasciatus) major satellite DNA (p=1.700 g/cm³) is mainly localized in the C-band-positive regions of all the microchromosomes. Our study of the behaviour of this satellite DNA byin situ hybridization has revealed a striking polarization of this DNA in the follicular epithelial cells of the ovary during oogenesis and in the spermatids during spermiogenesis. The major satellite DNA is localized at the point of the subsequent protrusion of the acrosomal pole of the round spermatid nuclei and remains in close contact with the developing sperm tip during the process of spermiogenesis. There appears to be an attraction between a specific region of the nuclear membrane and satellite-rich chromatin of the microchromosomes that brings about their polarization. We discuss possible functions of such extreme polarization of microchromosomes in specific cell types during oogenesis and spermiogenesis.