Msn2/Msn4-family zinc finger transcription factors play important roles in stress response in yeast. However, some members of this family show significant functional divergence in different species. Here, we report that in the dimorphic yeast Yarrowia lipolytica, the Msn2/Msn4-like protein Mhy1 is a key regulator of yeast-to-hypha dimorphic transition but not stress response. Both MHY1 deletion and overexpression affect filamentation. In contrast, YlMsn4, the other Msn2/Msn4-like protein, regulates tolerance to acid-induced stress. We show that MHY1 has an unusually long (about 3800 bp) promoter featuring an upstream located enhancer and a double stress response element (STRE) motif, the latter of which mediates Mhy1's regulation on its own transcription. Transcriptome profiling conducted in wild-type strain, mhy1Δ mutant and MHY1-overexpressing mutant revealed about 100 genes that are highly differentially expressed (≥ 5-fold) in each of the 2 mutants compared to the wild-type strain. The largest group of genes downregulated in mhy1Δ mutant encodes cell wall proteins or enzymes involved in cell wall organization, suggesting that Mhy1 may regulate dimorphic transition by controlling these cell wall genes. We confirmed that the genes YALI0C23452, YALI0C15268 and YALI0B09955 are directly regulated by Mhy1. We also characterized the Mhy1 consensus binding site as 5'-WNAGGGG-3' (W = A or T; N = A, T, G or C). These results provide new insight in the functions of Msn2/Msn4-family transcription factors in fungi and the mechanism by which Mhy1 regulates dimorphic transition.

中文翻译：

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Mhy1的启动子，下游目标基因和识别DNA序列的表征，Mhy1是双态酵母解脂耶氏酵母中一个关键的促进丝化的转录因子。

Msn2 / Msn4-家族锌指转录因子在酵母的应激反应中起重要作用。但是，该家族的某些成员在不同物种中显示出明显的功能差异。在这里，我们报告，在二形酵母解脂耶氏酵母中，Msn2 / Msn4-样蛋白Mhy1是酵母到菌丝二形转变但不是应激反应的关键调节因子。MHY1缺失和过表达都会影响丝状化。相反，另一种类似于Msn2 / Msn4-的蛋白质YlMsn4调节对酸诱导的胁迫的耐受性。我们显示MHY1具有异常长（约3800 bp）启动子，具有上游定位的增强子和双重应激反应元件（STRE）母题，后者介导Mhy1对其自身转录的调控。在野生型菌株中进行转录组分析，与野生型菌株相比，mhy1Δ突变体和MHY1过表达突变体揭示了约100个基因，在2个突变体的每一个中均高度差异表达（≥5倍）。在mhy​​1Δ突变体中下调的最大基因组编码细胞壁蛋白或参与细胞壁组织的酶，这表明Mhy1可以通过控制这些细胞壁基因来调节双态转化。我们证实，基因YALI0C23452，YALI0C15268和YALI0B09955直接受Mhy1调控。我们还将Mhy1共有结合位点定性为5'-WNAGGGG-3'（W = A或T； N = A，T，G或C）。这些结果提供了对真菌中Msn2 / Msn4-家族转录因子的功能和Mhy1调节双态转变的机制的新见解。