Non-histone chromosomal proteins

HMGBl was first described as a non-histone chromosomal protein [1,80] and has been implicated in the maintenance and establishment of chromatin structure [10] as well as having more recently identified roles. 

Nagaki, S., Yamamoto, M., Yumoto, Y., Shirakawa, H., Yoshida, M., and Teraoka, H. (1998) Non-histone chromosomal proteins HMGl and 2 enhance ligation reaction of DNA double-strand breaks. Biochem. Biophys. Res. Commun. 246, 137-141. 

Many other kinases have been studied, often in the context of regulation of some process by phosphorylation and dephosphorylation. Examples from muscle regulation have already been given. A further example is the transcription of eukaryotic DNA, which may be regulated by phosphorylation of non-histone chromosomal proteins. A number of nuclear protein kinases have been partially purified. These have an absolute requirement for divalent cations, and are not stimulated by 3, 5 -cyclic AMP (cAMP).287,288... 

Although complexes of DNA and histones form the nucleosomal substructures of chromatin, other types of proteins are also associated with DNA in the nucleus. These proteins were given the unimaginative name of non-histone chromosomal proteins. The cells of different tissues contain different amounts and types of these proteins, which include enzymes that act on DNA and factors that regulate transcription. 

Cary PD, Turner CH, Mayes E, Crane-Robinson C (1983) Conformation and domain structure of the non-histone chromosomal proteins, HMG 1 and 2. Eur J Biochem 131 367-374... 

The chromatin fibres form a series of loops which are fixed to a scaffold matrix (50 loops per turn). The scaffold matrix is made of a non-histone chromosomal protein ... 

Lectins may be used as probes for the study of the organization of specific components of chromatin. Three glycoproteins (mol. wt. 6.9 x 10 , 1.25, and 1.35 x 10 ) have been isolated from the non-histone chromosomal proteins from rat liver nuclei. The H-2 major histocompatibility complex is a complex of genes on murine chromosome 17, and is recognised as controlling the rejection of tissue allografts. Of five major peptides isolated from a... 

Peterson, J. L., and McConkey, E. H., 1976, Non-histone chromosomal proteins from HeLa cells, J. Biol. Chem. 251 548. 

Stein, G., and Baserga, R., 1970, Continued synthesis of non-histone chromosomal proteins during mitosis, Biochem. Biophys. Res. Commun. 41 715. 

Nucleoprotein heteropolar complexes of nucleic acids (in particular, nuclear DNA) with basic, acid-soluble proteins (histones or protamines), and with acidic, base- or detergent-soluble non-histone chromatin proteins. N. occur mainly in the chromatin of the cell nucleus in its quiescent state, and in the chromosomes when the nucleus is active, i.e. dividing. Many viruses consist entirely of N., but N. are absent from bacteria. N. are concerned in DNA replication, and in the control of gene function during protein biosynthesis. 

Chromatin The material of chromosomes. It is a complex of DNA, histones, and nonhistone proteins (chromosomal proteins, non-histone) found within the nucleus of a cell. [NIH]... 

Another group of non-histone proteins have been identified as essential components for the formation of the condensed chromosome (Table 1). Topoisomerase II (topo II) localizes in the scaffold/matrix fraction of the interphase nuclear (Berrios et al., 1985) and the mitotic chromosome (Maeshima and Laemmli, 2003) (see section 3.1). Topo II forms a ring-shaped homodimer (Berger et al, 1996 Nettikadan et al, 1998) and catalyzes the decatenation and relaxation of DNA double strand (Wang, 2002). In fission yeast, chromosomes cannot be condensed without functional topo II (Uemura et al, 1987). In addition, in in vitro experiment, mitotic extracts containing topo II induce chromatin condensation in the isolated nuclei from HeLa and chicken erythrocyte cells (Adachi et al., 1991). 

The spectrum of pleiotropic functions of different HI variants in different taxa has yet to be established. With respect to interactions within chromatin, the elucidation of the role of linker histones in transmitting or enhancing the effects of other non-histone proteins will be of particular interest. Given the dynamic behavior of HI in the nucleus, the possibility of auxiliary extrachromosomal functions performed by the free HI pool should be explored. An example of such a function is the recent finding that free HI is involved in the import of adenovirus DNA into the nucleus [158]. Other potential functions, especially at the period of maximum chromatin condensation, could depend on the gradient of free HI around the chromosomes. 

The first indication that modification of specific tail residues were linked to chromatin functional states, came from immunostaining of Drosophila polytene chromosomes with antibodies specific for H4 acetylated at defined lysines [13]. As shown in Fig. 2A, H4 acetylated at lysine 16 (H4acK16) was found almost exclusively on the transcriptional hyperactive male X chromosome (Fig. 2). (Genes on the Drosophila male X are transcribed twice as fast as their female counterparts so as to equalize levels of X-linked gene products between XY males and XX females.) In addition, H4 lysine 12 was found to remain acetylated in centric heterochromatin, while lysines 5, 8, and 16 were all under-acetylated [13]. These observations led to the suggestion that the histone N-terminal tails constitute nucleosome surface markers that can be recognized by non-histone proteins in a modification-dependent manner to alter the functional state of chromatin [13]. 

Potentized homeopathic drugs are capable of producing effects on both prokaryotic and eukaryotic cells. Prokaryotic cells are usually smaller in size (1 - 10 pm) than eukaryotic ones (5 - 100 pm). Membrane-bound organelles like mitochondria, endoplasmic reticulum, Golgi complexes etc. are present in eukaryotic cells but absent in prokaryotic ones. While eukaryotic cells have nucleus containing DNA with histone and non-histone proteins in chromosoms, prokaryotic cells have no nucleus and their DNA with non-histone proteins lies in nucleoid without any membranous envelope. However, both types of cells are covered by plasma membrane with some common features. 

The nuclear receptor is an intrinsic chromosomal acidic non-histone protein whose localization in the nucleus is not dependent on the presence of the hormone. It can be extracted by salts [36] yielding a 3.5-3.8 S [37] protein having a molecular mass... 

Chromatin is the complex combination of DNA, RNA and protein that makes up chromosomes inside the nuclei of eukaryotic cells it is divided between heterochromatin (condensed) and euchromatin (extended) forms. The functions of chromatin are to package DNA into a smaller volume to fit into the cell, to support the DNA to allow mitosis and meiosis, and to serve as a mechanism to control expression and DNA replication. Changes in chromatin strncture are affected by chemical modifications of histone proteins, such as methylation (DNA and proteins) and acetylation (proteins), and by non-histone DNA-binding proteins. Chromatin is easily visualised by staining, hence its name, which literally means coloured, lightened material. 

Chromatin, is a complex of DNA, histones and other non-histone proteins. The chromosomes in the nucleus of eukaryotic cells exist as chromatin complexes. 

Eukaryote chromosomes contain roughly equal amounts of DNA and protein. The proteins present are divided into two categories, histones and non-histone proteins. The former are small basic... 

Since adriamycin and daunomycin bind strongly to DNA, chromosomal DNA is assumed to be their site of action within the nucleus, although they can also bind weakly to acidic non-histone proteins [105]. The finding that both drugs... 

There are at least three types of chromosomal proteins histones, protamines, and residual proteins [58-63]. It has been estimated that the nuclear histones represent 90-92% of the total protein in the chromosome. The remaining portion (8-10%) is composed of the residual protein, or non histone proteins. 

Lipid-based carriers, polycationic lipids, polylysine, polyornithine, histones and other chromosomal proteins, hydrogel polymers, all of which can ionically condense DNA and bind to the cell surface are found to be ideal candidates for these vector type. But in the use of different types of cationic liposomes, cationic polymers and dendrimers as non-viral vectors for delivery of genes, it has been observed that in addition to cytotoxicity, these carriers do not lead to satisfactory amount of gene expression in the cells. The reasons are many, particularly, low endosomal escape, no protection of DNA from nuclease... 

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