Proteome analysis of human metaphase chromosomes

Susumu Uchiyama, Shouhei Kobayashi, Hideaki Takata, Takeshi Ishihara, Naoto Hori, Tsunehito Higashi, Kayoko Hayashihara, Takefumi Sone, Daisuke Higo, Takashi Nirasawa, Toshifumi Takao, Sachihiro Matsunaga, Kiichi Fukui. Proteome Analysis of Human Metaphase Chromosomes. Journal of Biological Chemistry, Volume 280, Issue 17, 2005, Pages 16994-17004. https://doi.org/10.1074/jbc.M412774200.

DNA is packaged as chromatin in the interphase nucleus. Dining mitosis, chromatin fibers are highly condensed to form metaphase chromosomes, which ensure equal segregation of replicated chromosomal DNA into the daughter cells. Despite > 1 century of research on metaphase chromosomes, information regarding the higher order structure of metaphase chromosomes is limited, and it is still not clear which proteins are involved in further folding of the chromatin fiber into metaphase chromosomes. To obtain a global view of the chromosomal proteins, we performed proteome analyses on three types of isolated human metaphase chromosomes. We first show the results from comparative proteome analyses of two types of isolated human metaphase chromosomes that have been frequently used in biochemical and morphological analyses. 209 proteins were quantitatively identified and classified into sis groups on the basis of their known interphase localization. Furthermore, a list of 107 proteins was obtained from the proteome analyses of highly purified metaphase chromosomes, the majority of which are essential for chromosome structure and function. Based on the information obtained on these proteins and on their localizations during mitosis as assessed by immunostaining, we present a four-layer model of metaphase chromosomes. According to this model, the chromosomal proteins have been newly classified into each of four groups: chromosome coating proteins, chromosome peripheral proteins, chromosome structural proteins, and chromosome fibrous proteins. This analysis represents the first compositional view of human metaphase chromosomes and provides a protein frame-work for future research on this topic.