Departments of Immunology and Biochemistry, University of Washington, Seattle, Washington, USA.
Ann N Y Acad Sci. 2012 Sep;1267:53-60. doi: 10.1111/j.1749-6632.2012.06586.x.
The G4 motif, G(≥3) N(x) G(≥3) N(x) G(≥3) N(x) G(≥3) , is enriched in some genomic regions and depleted in others. This motif confers the ability to form an unusual four-stranded DNA structure, G4 DNA. G4 DNA is associated with genomic instability, which may explain depletion of G4 motifs from some genes and genomic regions. Conversely, G4 motifs are enriched downstream of transcription start sites, where they correlate with pausing. The uneven distribution of G4 motifs in the genome strongly suggests that mechanisms of selection act not only on one-dimensional genomic sequence, but also on structures formed by genomic DNA. The biological roles of G4 structures illustrate that, to understand genome function, it is important to consider the dynamic structural potential implicit in the G4 motif.
G4 基序,G(≥3)N(x)G(≥3)N(x)G(≥3)N(x)G(≥3),在一些基因组区域富集而在其他区域匮乏。这个基序赋予了形成一种不寻常的四链 DNA 结构,G4 DNA 的能力。G4 DNA 与基因组不稳定性有关,这可能解释了一些基因和基因组区域中 G4 基序的缺失。相反,G4 基序在转录起始位点下游富集,与暂停相关。基因组中 G4 基序的不均匀分布强烈表明,选择机制不仅作用于一维基因组序列,还作用于基因组 DNA 形成的结构。G4 结构的生物学作用表明,为了理解基因组功能,考虑 G4 基序中隐含的动态结构潜力非常重要。