Chromosome assembly

Acetylation of core histones is associated with chromosomal assembly during DNA replication. 

Adachi Y, Luke M, Laemmli UK (1991) Chromosome assembly in vitro topoisomerase 11 is required for condensation. Cell 64 137-148... 

Lu W, Peterson R, Dasgupta A, Scovell WM (2000) Influence of HMG-1 and adenovirus oncoprotein ElA on early stages of transcriptional preinitiation complex assembly. J Biol Chem 275 35006-35012 Luger K, Mader AW, Richmond RK, Sargent DF, Richmond TJ (1997) Crystal structure of the nucle-osome core particle at 2.8 A resolution. Nature 389 251—260 Lusser A, Kadonaga JT (2004) Strategies for the reconstitution of chromatin. Nat Methods 1 19-26 Maeshima K, Laemmli UK (2003) A two-step scaffolding model for mitotic chromosome assembly. Dev Cell 4 467-480... 

Scrittori L, Hans F, Angelov D, Charra M, Prigent C, Dimitrov S (2001) pEg2 aurora-A kinase, histone H3 phosphorylation, and chromosome assembly in Xenopus egg extract. J Biol Chem 276(32) 30002-30010... 

Maeshima K, Laemmli UK. A two-step scaffolding model for mitotic chromosome assembly. Dev. Cell. 2003 4 467-480. 

Ono T, et al. Spatial and temporal regulation of Condensins I and II in mitotic chromosome assembly in human cells. Mol. Biol. Cell. 2004 15 3296-3308. 

Chromosomes are extremely complex chemicals that are assembled from simple repeating units and contain all the chemical information needed to reproduce animate species. Each living organism has its own complete set of chromosomes, called the genome. 

Nucleus The nucleus is separated from the cytosol by a double membrane, the nuclear envelope. The DNA is complexed with basic proteins (histones) to form chromatin fibers, the material from which chromosomes are made. A distinct RNA-rich region, the nucleolus, is the site of ribosome assembly. The nucleus is the repository of genetic information encoded in DNA and organized into chromosomes. During mitosis, the chromosomes are replicated and transmitted to the daughter cells. The genetic information of DNA is transcribed into RNA in the nucleus and passes into the cytosol where it is translated into protein by ribosomes. 

The activated CDKl-cyclin B kinase finally phosphor-ylates a large number of proteins most of which are not well characterized, leading to chromosome condensation, nuclear envelope breakdown, spindle assembly, and chromosome segregation. 

A signal transduction pathway required for proper chromosome alignment during mitosis. The spindle assembly checkpoint is activated during mitosis in response to the presence of chromosomes that are not attached to spindle microtubules or that are not properly aligned at the metaphase plate. The spindle checkpoint... 

Wadsworth, P. (1993). Mitosis spindle assembly and chromosome motion. Curr. Opin. Cell Biol. 5, 123-128. 

An important consideration for DNA CT in the cell is the dramatically different environment of the DNA molecule in vivo. Unlike the naked DNA typically used in our in vitro assemblies, cellular DNA is intimately associated with proteins, packaged into chromosomes, and stored in the cell nucleus. Several experimental investigations demonstrate definitively that proteins can both modulate and participate in CT reaction in DNA. 

The duration of the M phase is largely determined by the time necessary for the formation of a functional metaphase spindle and the correct alignment of all chromosomes in the metaphase plate. The spindle assembly checkpoint prevents the exit from the M phase before the proper alignment of all chromosomes into a metaphase plate in many cell types. This kind of control is already operational... 

Adolph KW, Kreisman LR, Kuehn RL (1986) Assembly of chromatin fibers into metaphase chromosomes analyzed by transmission electron microscopy and scanning electron microscopy. Biophys J 49 221-231... 

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