Graduate School of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Japan.
Department of Integrative Studies of Plant and Animal Production, School of Food Industrial Sciences, Miyagi University, 2-2-1 Hatatate, Sendai 982-0215, Japan.
Cells. 2022 Apr 28;11(9):1486. doi: 10.3390/cells11091486.
Heat stress responses are complex regulatory processes, including sensing, signal transduction, and gene expression. However, the exact mechanisms of these processes in seaweeds are not well known. We explored the relationship between membrane physical states and gene expression in the red alga . To analyze heat-stress-induced gene expression, we identified two homologs of the heat-inducible () gene in , named and . We found conservation of homologs only within the order Bangiales; their products contained a novel conserved cysteine repeat which we designated the Bangiales cysteine-rich motif. A quantitative mRNA analysis showed that expression of and was induced by heat stress. However, the membrane fluidizer benzyl alcohol (BA) did not induce expression of these genes, indicating that the effect of heat was not due to membrane fluidization. In contrast, expression of genes encoding multiprotein-bridging factor 1 () and HSP70s ( and ) was induced by heat stress and by BA, indicating that it involved a membrane-fluidization-dependent pathway. In addition, dark treatment under heat stress promoted expression of , , , and , but not ; expression of and was membrane-fluidization-independent, and that of other genes was membrane-fluidization-dependent. These findings indicate that the heat stress response in involves membrane-fluidization-dependent and -independent pathways.
热应激反应是复杂的调节过程，包括感受、信号转导和基因表达。然而，海藻中这些过程的确切机制尚不清楚。我们探讨了红藻中膜物理状态与基因表达之间的关系。为了分析热应激诱导的基因表达，我们在 中鉴定了两个热诱导基因 ()的同源物，分别命名为 和 。我们发现同源物的保守性仅存在于 Bangiales 目中；它们的产物含有一个新的保守半胱氨酸重复序列，我们将其命名为 Bangiales 富含半胱氨酸基序。定量 mRNA 分析表明， 和 的表达受热应激诱导。然而，膜流动性调节剂苯甲醇 (BA) 并未诱导这些基因的表达，表明热的作用不是由于膜流动性增加。相反，多蛋白桥接因子 1 () 和 HSP70s ( 和 ) 的基因表达受热应激和 BA 诱导，表明它涉及一个依赖于膜流动性的途径。此外，热应激下的暗处理促进了 、 、 、 和 的表达，但不促进 的表达； 和 的表达与膜流动性无关，而其他基因的表达与膜流动性有关。这些发现表明， 在热应激反应中涉及膜流动性依赖和非依赖途径。
