Department of Microbiology and Molecular Biology, College of Bioscience and Biotechnology, Chungnam National University, Daejeon, 34134, Republic of Korea.
J Microbiol. 2020 Oct;58(10):853-858. doi: 10.1007/s12275-020-0431-7. Epub 2020 Sep 29.
In yeast Saccharomyces cerevisiae, the Dhh1 protein, a member of the DEAD-box RNA helicase, stimulates Dcp2/Dcp1-mediated mRNA decapping and functions as a general translation repressor. Dhh1 also positively regulates translation of a selected set of mRNAs, including Ste12, a transcription factor for yeast mating and pseudohyphal growth. Given the diverse functions of Dhh1, we investigated whether the putative phosphorylation sites or the conserved motifs for the DEAD-box RNA helicases were crucial in the regulatory roles of Dhh1 during pseudohyphal growth. Mutations in the ATPase A or B motif (DHH1-K96R or DHH1-D195A) showed significant defects in pseudohyphal colony morphology and agar invasive phenotypes. The N-terminal phospho-mimetic mutation, DHH1-T16E, showed defects in pseudohyphal phenotypes. Decreased levels of Ste12 protein were also observed in these pseudohyphal-defective mutant cells under filamentous-inducing low nitrogen conditions. We suggest that the ATPase motifs and the Thr16 phosphorylation site of Dhh1 are crucial to its regulatory roles in pseudohyphal growth under low nitrogen conditions.
在酵母酿酒酵母中，Dhh1 蛋白是 DEAD 盒 RNA 解旋酶的成员，它能刺激 Dcp2/Dcp1 介导的 mRNA 脱帽，并作为一种通用的翻译抑制剂发挥作用。Dhh1 还能正向调控一组选定的 mRNA 的翻译，包括 Ste12，这是一种酵母交配和假菌丝生长的转录因子。鉴于 Dhh1 具有多种功能，我们研究了假定的磷酸化位点或 DEAD 盒 RNA 解旋酶的保守基序是否对 Dhh1 在假菌丝生长过程中的调节作用至关重要。ATP 酶 A 或 B 基序（DHH1-K96R 或 DHH1-D195A）中的突变在假菌丝集落形态和琼脂侵袭表型上表现出明显的缺陷。N 端磷酸模拟突变 DHH1-T16E 也表现出假菌丝表型缺陷。在低氮条件下诱导丝状生长时，这些假菌丝缺陷突变细胞中的 Ste12 蛋白水平也降低。我们认为，在低氮条件下，Dhh1 的 ATP 酶基序和 Thr16 磷酸化位点对其在假菌丝生长中的调节作用至关重要。
