Genetics Graduate Interdisciplinary Program, The University of Arizona, Tucson, AZ 85724, USA.
Genetics Graduate Interdisciplinary Program, The University of Arizona, Tucson, AZ 85724, USA; Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, AZ 85724, USA.
Semin Cell Dev Biol. 2023 Feb 28;136:38-48. doi: 10.1016/j.semcdb.2022.05.006. Epub 2022 May 18.
The ribosomal DNA (rDNA) in Drosophila is found as two additive clusters of individual 35 S cistrons. The multiplicity of rDNA is essential to assure proper translational demands, but the nature of the tandem arrays expose them to copy number variation within and between populations. Here, we discuss means by which a cell responds to insufficient rDNA copy number, including a historical view of rDNA magnification whose mechanism was inferred some 35 years ago. Recent work has revealed that multiple conditions may also result in rDNA loss, in response to which rDNA magnification may have evolved. We discuss potential models for the mechanism of magnification, and evaluate possible consequences of rDNA copy number variation.
果蝇的核糖体 DNA（rDNA）存在于两个单独的 35S 顺式元件的附加簇中。rDNA 的多样性对于确保适当的翻译需求至关重要，但串联阵列的性质使它们容易受到种群内和种群间的拷贝数变异的影响。在这里，我们讨论了细胞对 rDNA 拷贝数不足的反应方式，包括大约 35 年前推断出的 rDNA 扩增机制的历史观点。最近的工作表明，多种条件也可能导致 rDNA 丢失，对此，rDNA 扩增可能已经进化。我们讨论了放大机制的潜在模型，并评估了 rDNA 拷贝数变异的可能后果。
