A sophisticated two-component signaling system regulates the meiotic cell differentiation in response to oxidative stress in S.pombe.

Pombe的性别分化似乎是由环境胁迫诱导的，如氮饥饿。Ste11的表达是性别分化的关键，其信息素介导的信号通路的分子机制已有相当多的文献报道。然而，关于环境信号(S)是如何被感知并传递到下游元素来执行性分化的，我们知之甚少。对于这个特殊的问题，我们在这里提供的证据表明，一个两组分的信号转导系统发挥了关键作用，其中三个组氨酸激酶(Phk1/2/3)，一个HPT因子(Spy1)和两个反应调节因子(Mcs4和Ptt1)与下游的Sty1 MAPK级联一起发挥作用。这种复杂的信号机制被证明参与了对氧化胁迫反应的减数分裂的诱导，直接触发了减数分裂初始阶段所需的ate11、mama2和mei2基因的表达。这是细菌类型的His-Asp磷酸传递信号与真核细胞周期控制的基本过程密切相关的第一个迹象。我们还发现，拟南芥AHK4组蛋白激酶在裂解酵母S.pombe中作为细胞分裂素反应感受器发挥作用。

The sexual differentiation of S.pombe appears to be induced by environmental stress, such as nitrogen starvation. The expression of ste11 is crucial for sexual differentiation, and its molecular mechanisms of pheromon-mediated signal pathway have fairly well-documented. However, litlle is known about how the environmental signal(s) is perceived and relayed to the downstream elements to execute the sexual differentiation. With regard to this particular issue, here we provide evidens that a two-component signal transduction system pay a crucial role, in whichthree histidine-kinases(Phk1/2/3), one Hpt factor (Spy1) and two response-regulators(Mcs4 and Ptt1) act in concert with the downstream Sty1 MAPK cascade. This sophisticated signaling mechanism was demonstrated to be involved in the induction of meiosis in response to oxidative stress, through directly triggering the induction of expression of gene such as ate11, mam2, and mei2, which are required in the initial stage of meiosis. This is the first indication that a bacterial type of His-Asp phosphorelay signaling is closely linked to the fundamental process og eukaryotic cell cycle control. We also showed that the Arabidopis AHK4 His kinase functions as a cytokinin responsive sensor in the fission yeast, S.pombe.