Scientists who study chromosomal proteins expect to find them on chromosomes, which is why Michel Bellini, a professor of cell and structural biology in LAS, and graduate student Brent Beenders were surprised to discover the chromosomal protein XCAP-E segregated from the others. They used a technique called confocal laser scanning microscopy to pinpoint the distribution of two chromosomal associated proteins (CAP) in the nuclei of frog oocytes and found XCAP-E sitting in the nucleoli instead of on the chromatin that was undergoing meiosis, or reproductive cell division.
Bellini and Beenders propose that the protein XCAP-E may not be required in the early stages of meiosis, but used later during condensation, when chromatins in the cell nuclei segregate into discrete packages of DNA, called chromosomes, prior to cell division. In contrast, the protein XCAP-D2 was found primarily on chromosomes. XCAP-D2, they say, may be important in the early organization of chromosomes and later may recruit other key chromosomal proteins, such as XCAP-E.
The proteins have equivalents in other organisms, thus the scientists' findings may advance the study of chromosome physiology and how these proteins function in chromatin condensation. At the critical time of cell division, chromosome packaging is vital. Genetic errors can result in deformities, diseases such as cancer and/or the death of the organism.
