Domain of Unknown Function (DUF) genes are broadly conserved in metazoa but have an unknown biological function. Previously, we established transcriptional profiles of the germline and stem cells of the flatworm Macrostomum lignano (Grudniewska et al., 2016). Here, we used this information to probe the function of DUF genes in M. lignano. Recently, Kang et al. (2016) found that DUF2366 is a mitochondrial inner membrane protein that interacts with the protein import complex TIM22. DUF2366 was renamed TIM29, and shown to stabilize the TIM22 complex, but its biological role remained largely unknown. We now demonstrate that DUF2366/TIM29 is dispensable in the homeostatic condition in M. lignano, but is essential to adapt to a highly proliferative state required for regeneration. Our results show that 'de-DUFing' the function of DUF genes might require special biological conditions, such as regeneration, and establishes M. lignano as an informative platform to study DUF genes.

中文翻译：

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在扁虫Macrostomum lignano中再生期间干细胞活性需要Tim29

未知功能域（DUF）基因在后生动物中广泛保守，但生物学功能未知。以前，我们建立了扁虫Macrostomum lignano的种系和干细胞的转录谱（Grudniewska等人，2016）。在这里，我们用这个信息来探测在DUF基因的功能M.利加诺。最近，康等。（2016）发现DUF2366是一种线粒体内膜蛋白，可与蛋白质进口复合物TIM22相互作用。DUF2366被重命名为TIM29，并显示可稳定TIM22复合物，但其生物学作用仍然未知。现在，我们证明DUF2366 / TIM29在M. lignano中的稳态条件下是可有可无的，但对于适应再生所必需的高度增殖状态至关重要。我们的结果表明，“去DUF” DUF基因的功能可能需要特殊的生物学条件，例如再生，并建立了M. lignano作为研究DUF基因的信息平台。