Proteome analysis of human metaphase chromosomes.
DNA is packaged as chromatin in the interphase nucleus. During 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 six 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 framework for future research on this topic.
Uchiyama
Susumu
S
Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan.
Kobayashi
Shouhei
S
Takata
Hideaki
H
Ishihara
Takeshi
T
Hori
Naoto
N
Higashi
Tsunehito
T
Hayashihara
Kayoko
K
Sone
Takefumi
T
Higo
Daisuke
D
Nirasawa
Takashi
T
Takao
Toshifumi
T
Matsunaga
Sachihiro
S
Fukui
Kiichi
K
D002843:Chromatin / Q000378:metabolism; D002874:Chromosome Mapping; D002875:Chromosomes / Q000648:ultrastructure*; D019295:Computational Biology / Q000379:methods; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D013058:Mass Spectrometry; D008677:Metaphase; D008856:Microscopy, Fluorescence; D020543:Proteome; D040901:Proteomics / Q000379:methods*
D002843:Chromatin; D020543:Proteome