Faithful segregation of chromosomes is an extremely important part of life. Oocytes will undergo a type of cell division called meiosis, and extrude half of their genetic material prior to fertilization. If this process fails, and the genetic material divides incorrectly, the consequences are severe. When a cell divides, the division of the chromosomes is driven by a dynamic structure called the spindle. However, due to the limits of light resolution, there is not enough known about the mechanisms of spindle assembly. Understanding the interactions between the spindle and the chromosomes could provide valuable insight into chromosome mis-segregation, and why certain chromosomes are more likely to mis-segregate than others. The goal of this project was to access and image the spindle and chromosomes in mouse oocytes of different developmental stages: To label the spindle and the chromosomes, mRNA coding for fluorescently labeled proteins of interest was prepared and injected into the mouse oocytes. The spindle assembly and chromosome segregation will be studied in those Oocytes. The next step with this imaging technique is to image oocytes with certain proteins knocked down to analyze their impact on chromosomal division. The data collected will help explain the mechanisms of spindle assembly and correct segregation of chromosomes during meiotic cell division.