Spliceosomal introns are ubiquitous non-coding RNAs that are typically destined for rapid debranching and degradation. Here we describe 34 excised introns in Saccharomyces cerevisiae that—despite being rapidly degraded in log-phase growth—accumulate as linear RNAs under either saturated-growth conditions or other stresses that cause prolonged inhibition of TORC1, which is a key integrator of growth signalling. Introns that become stabilized remain associated with components of the spliceosome and differ from other spliceosomal introns in having a short distance between their lariat branch point and 3′ splice site, which is necessary and sufficient for their stabilization. Deletion of these unusual introns is disadvantageous in saturated conditions and causes aberrantly high growth rates in yeast that are chronically challenged with the TORC1 inhibitor rapamycin. The reintroduction of native or engineered stable introns suppresses this aberrant rapamycin response. Thus, excised introns function within the TOR growth-signalling network of S. cerevisiae and, more generally, excised spliceosomal introns can have biological functions.A set of 34 excised introns in Saccharomyces cerevisiae, characterized by having a short distance between the lariat branch point and the 3′ splice site, have a biological function within the TOR growth-signalling network.

中文翻译：

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切除的线性内含子调节酵母的生长

剪接体内含子是普遍存在的非编码 RNA，通常注定要快速脱支和降解。在这里，我们描述了酿酒酵母中 34 个切除的内含子——尽管在对数期生长中迅速降解——在饱和生长条件或导致长期抑制 TORC1 的其他压力下作为线性 RNA 积累，TORC1 是生长信号的关键整合子。变得稳定的内含子仍然与剪接体的成分相关，并且与其他剪接体内含子的不同之处在于它们的套索分支点和 3' 剪接位点之间的距离很短，这对于它们的稳定是必要和充分的。这些不寻常的内含子的缺失在饱和条件下是不利的，并导致长期受到TORC1抑制剂雷帕霉素挑战的酵母的异常高生长速率。重新引入天然或工程化的稳定内含子抑制了这种异常的雷帕霉素反应。因此，切除的内含子在酿酒酵母的 TOR 生长信号网络中发挥作用，更一般地说，切除的剪接体内含子可以具有生物学功能。 酿酒酵母中的一组 34 个切除的内含子，其特征在于套索分支点之间的距离较短和 3' 剪接位点在 TOR 生长信号网络中具有生物学功能。