A chromomeric model for nuclear and chromosome structure

1995 ◽  
Vol 108 (9) ◽  
pp. 2927-2935 ◽  
Author(s):  
P.R. Cook
Keyword(s):  
Transcription Factors ◽  
Chromosome Structure ◽  
Rna Polymerases ◽  
Stable Structure ◽  
Structural Elements ◽  
Transcription Factories ◽  
Chromatin Loops ◽  
Sticky End

The basic structural elements of chromatin and chromosomes are reviewed. Then a model involving only three architectural motifs, nucleosomes, chromatin loops and transcription factories/chromomeres, is presented. Loops are tied through transcription factors and RNA polymerases to factories during interphase and to the remnants of those factories, chromomeres, during mitosis. On entry into mitosis, increased adhesiveness between nucleosomes and between factories drives a ‘sticky-end’ aggregation to the most compact and stable structure, a cylinder of nucleosomes around an axial chromomeric core.

Transcription factories and chromosome structure

1997 ◽  
pp. 147-160 ◽  
Author(s):  
A. Pombo ◽  
J. McManus ◽  
T. A. Hughes ◽  
F. J. Iborra ◽  
D. A. Jackson ◽  
...  
Keyword(s):  
Chromosome Structure ◽  
Transcription Factories

scholarly journals CTCF: the protein, the binding partners, the binding sites and their chromatin loops

2013 ◽  
Vol 368 (1620) ◽  
pp. 20120369 ◽  
Author(s):  
Sjoerd Johannes Bastiaan Holwerda ◽  
Wouter de Laat
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Rna Polymerase Ii ◽  
Binding Sites ◽  
Ctcf Binding ◽  
Chromatin Domain ◽  
Gene Promoters ◽  
Tissue Specific ◽  
Chromatin Loops ◽  
Exact Function

CTCF has it all. The transcription factor binds to tens of thousands of genomic sites, some tissue-specific, others ultra-conserved. It can act as a transcriptional activator, repressor and insulator, and it can pause transcription. CTCF binds at chromatin domain boundaries, at enhancers and gene promoters, and inside gene bodies. It can attract many other transcription factors to chromatin, including tissue-specific transcriptional activators, repressors, cohesin and RNA polymerase II, and it forms chromatin loops. Yet, or perhaps therefore, CTCF's exact function at a given genomic site is unpredictable. It appears to be determined by the associated transcription factors, by the location of the binding site relative to the transcriptional start site of a gene, and by the site's engagement in chromatin loops with other CTCF-binding sites, enhancers or gene promoters. Here, we will discuss genome-wide features of CTCF binding events, as well as locus-specific functions of this remarkable transcription factor.

scholarly journals The proteomes of transcription factories containing RNA polymerases I, II or III

2011 ◽  
Vol 8 (11) ◽  
pp. 963-968 ◽  
Author(s):  
Svitlana Melnik ◽  
Binwei Deng ◽  
Argyris Papantonis ◽  
Sabyasachi Baboo ◽  
Ian M Carr ◽  
...  
Keyword(s):  
Rna Polymerases ◽  
Transcription Factories

scholarly journals Active RNA polymerases are localized within discrete transcription “factories' in human nuclei

1996 ◽  
Vol 109 (6) ◽  
pp. 1427-1436 ◽  
Author(s):  
F.J. Iborra ◽  
A. Pombo ◽  
D.A. Jackson ◽  
P.R. Cook
Keyword(s):  
Electron Microscopy ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Hela Cells ◽  
Rna Polymerases ◽  
Transcription Factories ◽  
Nascent Rna ◽  
Nascent Transcripts ◽  
Typical Site

Nascent transcripts in permeabilized HeLa cells were elongated by approximately 30–2,000 nucleotides in Br-UTP or biotin-14-CTP, before incorporation sites were immunolabelled either pre- or post-embedding, and visualized by light or electron microscopy. Analogues were concentrated in approximately 2,100 (range 2,000-2,700) discrete sites attached to a nucleoskeleton and surrounded by chromatin. A typical site contained a cluster (diameter 71 nm) of at least 4, and probably about 20, engaged polymerases, plus associated transcripts that partially overlapped a zone of RNA polymerase II, ribonucleoproteins, and proteins rich in thiols and acidic groups. As each site probably contains many transcription units, these results suggest that active polymerases are confined to these sites, which we call transcription ‘factories’. Results are consistent with transcription occurring as templates slide past attached polymerases, as nascent RNA is extruded into the factories.

Molecular mechanisms of archaeal RNA polymerase

2009 ◽  
Vol 37 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Dina Grohmann ◽  
Angela Hirtreiter ◽  
Finn Werner
Keyword(s):  
Transcription Factors ◽  
Nucleic Acid ◽  
Rna Polymerase ◽  
Molecular Mechanisms ◽  
Structural Information ◽  
Rna Polymerases ◽  
Nucleic Acid Binding ◽  
Regulatory Interactions ◽  
Cellular Life ◽  
Domains Of Life

All cellular life depends on multisubunit RNAPs (RNA polymerases) that are evolutionarily related through the three domains of life. Archaeal RNAPs encompass 12 subunits that contribute in different ways to the assembly and stability of the enzyme, nucleic acid binding, catalysis and specific regulatory interactions with transcription factors. The recent development of methods to reconstitute archaeal RNAP from recombinant materials in conjunction with structural information of multisubunit RNAPs present a potent opportunity to investigate the molecular mechanisms of transcription.

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