Centriolar satellites associate with condensed chromatin in early mouse oocytes and undergo redistribution during transition to dictyate

Abstract

In eukaryotic cells during interphase, the centrosome is positioned close to the nucleus by a yet unidentified mechanism and determines the basic cell polarity. The aim of this study was to trace the dynamics of centriolar satellite protein PCM-1 in newborn mouse ovaria. Ovarian sections of newborn mice were subjected to immunofluorescent analysis. The intracellular localization of PCM-1 in prophase I oocytes was compared between 1- and 2-day-old mice. In oocytes from 1-day-old ovaria, double or broader single discrete PCM-1 aggregates with perinuclear localization were observed in association with condensed chromatin regions. In oocytes from 2-day-old ovaria, PCM-1 structures were less discrete and chromatin was homogenous. In some oocytes, single or double PCM-1 aggregate was still recognizable, while in others, the PCM-1-containing structure was crescent-shaped. Our study describes for the first time reorganization of centriolar satellite protein PCM-1 in prophase I oocytes from developing primordial follicles correlated with chromatin changes during transition to dictyate.

Keywords

• Mammalian oocytes
• centriolar satellites
• PCM-1 protein
• immunofluorescence
• newborn mouse ovaria