MICROTUBULE AND MICROFILAMENT ORGANIZATION IN MATURING HUMAN OOCYTES

Various stages of immature human oocytes were imaged for microtubule, microfilament and chromatin organization. After germinal vesicle break down, a small microtubule aster was observed near the condensed chroma tin, The asters appeared to elongate and encompass the condensed chrom atin, At metaphase I stage, microtubules were detected in the meiotic spindle. The meiotic spindle in metaphase II was a symmetric, barrel-s haped structure containing anastral broad poles, located peripherally and radially oriented. After germinal vesicle breakdown, treatment wit h taxol induced numerous cytoplasmic foci of microtubules, mainly in t he cortex of the oocyte, Microfilaments were observed as a relatively thick uniform area around the cell cortex and were also found near the germinal vesicle position. After germinal vesicle breakdown, the micr ofilaments were seen in both the cortex and around the female chromati n, In conclusion, this study suggests that both microtubules and micro filaments are closely associated with the reconstruction and proper po sitioning of chromatin after germinal vesicle breakdown and during mei otic maturation in human oocytes.