Gibson Carolyn W, Thomson Neil H, Abrams William R, Kirkham Jennifer
University of Pennsylvania School of Dental Medicine, Department of Anatomy and Cell Biology, 240 S. 40th Street, Philadelphia, PA 19104, USA.
Gene. 2005 Apr 25;350(1):15-23. doi: 10.1016/j.gene.2004.12.045.
A "nested" gene is located within the boundaries of a larger gene, often within an intron and in the opposite orientation. Such structures are common in bacteria and viruses, but have also been described in higher species as diverse as Drosophila and humans. Expression of nested and host genes may be simultaneously up-regulated due to use of common enhancers, or down-regulated through steric hindrance or interference caused by annealing of the complementary RNAs, leading to degradation. Methods for RNA analysis such as RT-PCR and in situ hybridization reveal the presence of specific mRNAs, but do not address regulation of expression within a single cell at a single genetic locus. Atomic force microscopy is a relatively new technology, which allows visualization of the movement of an RNA polymerase along a DNA template. The potential of this technology includes a greater molecular understanding of cellular decision making processes, leading to enhanced opportunities to intervene in disease progression through use of novel treatment modalities.
“嵌套”基因位于一个更大基因的边界内，通常在一个内含子中，且方向相反。这种结构在细菌和病毒中很常见，但在果蝇和人类等高等物种中也有描述。由于使用共同的增强子，嵌套基因和宿主基因的表达可能同时上调，或者通过互补RNA退火引起的空间位阻或干扰而下调，导致降解。诸如逆转录聚合酶链反应（RT-PCR）和原位杂交等RNA分析方法可揭示特定mRNA的存在，但无法解决单个细胞内单个基因座处的表达调控问题。原子力显微镜是一项相对较新的技术，它能够可视化RNA聚合酶沿DNA模板的移动。这项技术的潜力包括对细胞决策过程有更深入的分子理解，从而通过使用新型治疗方式增加干预疾病进展的机会。
