Figure 15

Differentiation of early oocytes and behavior of oocytes in secondary OSC cultures. A-C) Time lapse cinematography of oocyte development in secondary OSC culture. A) Early developing cell with a cytoplasmic tail (arrowhead). B) Multiple cytoplasmic eruptions (arrowheads). C) Development of the 50 micrometers oocyte-like cell (yellow arrowheads indicate cell surface, red arrowhead a polar body). Time in minutes':seconds". Movie segments are available in the Additional file 1, supplemental video S1. D-F) Day 3 secondary OSC culture stained for ZP (d3sc ZP) - 55 year old postmenopausal women three days afer seeding. D) Oocyte (o) with a "chain" of satellite cell (s), regressing satellites (rs), and satelite remnants (sr) interconnected by intercellular bridges (open white arrowheads) and surface ZP expression (open black arrowheads). The "leading" oocyte shows formation of the cell surface in the bridge (solid yellow arrowhead). Asterisk indicates cell nucleus and red arrowhead developing polar body. E) Two "leading" oocyte type cells with surface ZP expression, each of which shows expulsion of two polar bodies (red arrowheads) and retention of two pronuclei (asterisks). Yellow arrowheads indicate a line of separation from remnants of the "satellite" cells lacking surface ZP. F) Large oocyte (140 micrometers) with surface ZP expression (arrowhead), nucleus (asterisk), and germinal vesicle (gv).