The formation of the fungal mycelial network is facilitated by somatic cell fusion of germinating asexual spores (or germlings). Neurospora crassa germlings in close proximity display chemotropic growth that is dependent upon an intracellular network of mitogen-activated protein kinase (MAPK) signaling cascades. Approximately 80 genes involved in intercellular communication and fusion have been identified, including three mutants with similar morphological phenotypes: Δwhi-2, Δcsp-6, and Δamph-1. Here we show that WHI-2 localizes to the cell periphery and regulates endocytosis, mitochondrial organization, sporulation, and cell fusion. WHI-2 was required to transduce signals through a conserved MAPK pathway (NRC-1/MEK-2/MAK-2) and target transcription factors (PP-1/ADV-1). The amph-1 locus encodes a Bin/Amphiphysin/Rvs domain-containing protein and mis-expression of whi-2 compensated for the cell fusion and endocytosis deficiencies of a Δamph-1 mutant. The csp-6 locus encodes a haloacid dehalogenase phosphatase whose activity was essential for cell fusion. Although fusion-deficient with themselves, cells that lacked whi-2, csp-6, or amph-1 showed a low frequency of chemotropic interactions with wild type cells. We hypothesize that WHI-2 could be important for signal perception during chemotropic interactions via a role in endocytosis.

中文翻译：

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WHI-2通过MAP激酶信号传导复合物调节细胞间通讯。

萌发的无性孢子（或种芽）的体细胞融合促进了真菌菌丝网络的形成。紧密近缘的神经孢霉幼虫显示出趋化性生长，其依赖于丝裂原激活的蛋白激酶（MAPK）信号级联的细胞内网络。已经鉴定出大约80个参与细胞间通讯和融合的基因，包括三个具有相似形态表型的突变体：Δwhi-2，Δcsp-6和Δamph-1。在这里，我们显示WHI-2定位于细胞外围，并调节内吞作用，线粒体组织，孢子形成和细胞融合。需要WHI-2通过保守的MAPK途径（NRC-1 / MEK-2 / MAK-2）和靶转录因子（PP-1 / ADV-1）来转导信号。Amph-1基因座编码含有Bin / Amphiphysin / Rvs结构域的蛋白质，并且whi-2的错误表达补偿了Δamph-1突变体的细胞融合和内吞作用缺陷。csp-6基因座编码一种卤酸脱卤酶磷酸酶，其活性对于细胞融合至关重要。尽管与自身融合不足，但缺少whi-2，csp-6或amph-1的细胞与野生型细胞的化学相互作用的频率较低。我们假设WHI-2通过内吞作用在趋化相互作用期间对于信号感知可能很重要。amph-1或amph-1与野生型细胞之间的化学相互作用频率较低。我们假设WHI-2通过内吞作用在趋化相互作用期间对于信号感知可能很重要。amph-1或amph-1与野生型细胞之间的化学相互作用频率较低。我们假设WHI-2通过内吞作用在趋化相互作用期间对于信号感知可能很重要。