Engelberg David, Baskin Alexey, Ben Zaken Shelly, Marbach Irit
Department of Biological Chemistry, The Institute of Life Science, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Singapore-HUJ Alliance for Research and Enterprise, Mechanisms of Liver Inflammatory Diseases Program, National University of Singapore, Singapore 138602.
FEMS Yeast Res. 2025 Jan 30;25. doi: 10.1093/femsyr/foaf021.
Most laboratory strains of the yeast Saccharomyces cerevisiae are incapable of invading agar, to form large colonies (mats), and to develop filament-like structures (pseudohyphae). A prominent strain that manifests these morphologies is ∑1278b. While induced transcription of the FLO11 gene is critical for executing invasive growth, mat formation, and pseudohyphal growth, downregulation of the 'general stress response' also seems to be required. As this response is weak in ∑1278b cells, we assumed that they may be sensitives to stresses. We report, however, that they are resistant to various stressors, but severely sensitive specifically to NaCl. We found that this sensitivity is a result of mutations in the single ∑1278b's ENA gene, encoding P-type sodium ATPase. Other laboratory strains harbor three to five copies of ENA, suggesting that ∑1278b was selected against Ena activity. Obtaining ∑1278b cells that can grow on NaCl allows checking its effect on colony morphologies. In the presence of NaCl, ∑1278b/ENA1+ cells do not invade agar, and do not form pseudohyphae or mats. Thus, we have found the following: (i) The ∑1278b strain differs from other laboratory strains with respect to sensitivity to NaCl, because it has no active Na+ ATPase exporter. (ii) NaCl is a suppressor of invasiveness, filamentous growth, and mat formation.
大多数酿酒酵母实验室菌株无法侵入琼脂、形成大菌落（菌垫）以及发育丝状结构（假菌丝）。表现出这些形态的一个突出菌株是∑1278b。虽然FLO11基因的诱导转录对于进行侵袭性生长、菌垫形成和假菌丝生长至关重要，但“一般应激反应”的下调似乎也是必需的。由于这种反应在∑1278b细胞中较弱，我们推测它们可能对压力敏感。然而，我们报告称，它们对各种应激源具有抗性，但对NaCl特别敏感。我们发现这种敏感性是由于∑1278b单个ENA基因发生突变所致，该基因编码P型钠ATP酶。其他实验室菌株含有三到五个ENA拷贝，这表明∑1278b是因Ena活性而被筛选出来的。获得能够在NaCl上生长的∑1278b细胞可以检测其对菌落形态的影响。在有NaCl存在的情况下，∑1278b/ENA1 +细胞不会侵入琼脂，也不会形成假菌丝或菌垫。因此，我们发现了以下几点：（i）∑1278b菌株在对NaCl的敏感性方面与其他实验室菌株不同，因为它没有活性Na + ATP酶输出蛋白。（ii）NaCl是侵袭性、丝状生长和菌垫形成的抑制剂。
