Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto 4150-180, Portugal.
Development. 2011 Jan;138(2):349-57. doi: 10.1242/dev.054411.
The nucleolus is a subnuclear factory, the activity of which is required beyond ribosome biogenesis for the regulation of cell growth, death and proliferation. In both Drosophila and mammalian cells, the activity of the nucleolus is regulated by the proto-oncogene Myc. Myc induces the transcription of genes required for ribosome biogenesis and the synthesis of rRNA by RNA polymerase I, a nucleolar event that is rate limiting for cell growth. Here, we show that the fruit fly Nol12 homologue Viriato is a key determinant of nucleolar architecture that is required for tissue growth and cell survival during Drosophila development. We further show that viriato expression is controlled by Drosophila Myc (dMyc), and that the ability of dMyc to stimulate nucleolar and cellular growth depends on viriato expression. Therefore, viriato acts downstream of dMyc to ensure a coordinated nucleolar response to dMyc-induced growth and, thereby, normal organ development.
核仁是亚核工厂，其活性不仅需要参与核糖体生物发生，还需要参与细胞生长、死亡和增殖的调节。在果蝇和哺乳动物细胞中，核仁的活性受原癌基因 Myc 的调节。Myc 诱导核糖体生物发生所需基因的转录和 RNA 聚合酶 I 合成 rRNA，这是细胞生长的核仁限速事件。在这里，我们表明果蝇 Nol12 同源物 Viriato 是核仁结构的关键决定因素，它是果蝇发育过程中组织生长和细胞存活所必需的。我们进一步表明，viriato 的表达受果蝇 Myc（dMyc）的控制，dMyc 刺激核仁生长和细胞生长的能力取决于 viriato 的表达。因此，viriato 作为 dMyc 的下游因子，确保协调核仁对 dMyc 诱导的生长的反应，从而实现正常的器官发育。
