Isolation and functional analysis of a gene, tcsB, encoding a transmembrane hybrid-type histidine kinase from Aspergillus nidulans
Isolation and functional analysis of a gene, tcsB, encoding a transmembrane hybrid-type histidine kinase from Aspergillus nidulans
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DOI：
10.1128/aem.68.11.5304-5310.2002
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发表时间：
2002-11-01
影响因子：
4.4
通讯作者：
Nakajima, T
中科院分区：
文献类型：
--
作者：
Furukawa, K;Katsuno, Y;Nakajima, T
我们克隆并鉴定了一个新的构巢曲霉组氨酸激酶基因，tcsB，编码一个膜型双组分信号蛋白同源的酵母菌的传感器合成致死N-末端规则蛋白I（SLN 1），通过高渗透压甘油反应I（HOG 1）丝裂原活化蛋白激酶（MAPK）级联反应在酵母细胞中的信号在环境渗透刺激。从A。在nidulans cDNA文库中，我们分离到一个含有3，210-bp开放阅读框的阳性克隆，它编码一个由1，070个氨基酸组成的推定蛋白。预测的tcsB蛋白（TcsB）有两个可能的跨膜区域在其N-末端的一半，并具有高度的结构相似性，酵母Sln 1 p，跨膜杂交型组氨酸激酶。过表达的tcsB cDNA抑制致死的温度敏感的slin 1-ts酵母突变体。然而，其中保守的磷酸化位点His（552）残基或磷酸化位点Asp（989）残基已被替换的tcsB cDNA不能与sln 1-ts突变体互补。此外，引入tcsB cDNA到s1 n1三角洲sho 1三角洲酵母双突变体，其中缺乏两个传感器，抑制在高盐度介质中的致死率和激活HOG 1 MAPK。这些结果表明，TcsB功能作为一个β-受体组氨酸激酶。我们构建了一个A。tcsB基因缺失的nidulans菌株（tcsBDelta），并检查其表型。然而，出乎意料的是，tcsBDelta菌株在标准或胁迫培养基上的菌丝发育或形态学均未表现出可检测的表型。结果表明，A.与酵母SLN 1-HOG 1 MAPK级联相比，nidulans具有更复杂和更强的MAPK调节系统。
We cloned and characterized a novel Aspergillus nidulans histidine kinase gene, tcsB, encoding a membrane-type two-component signaling protein homologous to the yeast osmosensor synthetic lethal N-end rule protein I (SLN1), which transmits signals through the high-osmolarity glycerol response I (HOG1) mitogen-activated protein kinase (MAPK) cascade in yeast cells in response to environmental osmotic stimuli. From an A. nidulans cDNA library, we isolated a positive clone containing a 3,210-bp open reading frame that encoded a putative protein consisting of 1,070 amino acids. The predicted tcsB protein (TcsB) has two probable transmembrane regions in its N-terminal half and has a high degree of structural similarity to yeast Sln1p, a transmembrane hybrid-type histidine kinase. Overexpression of the tcsB cDNA suppressed the lethality of a temperature-sensitive osmosensing-defective sln1-ts yeast mutant. However, tcsB cDNAs in which the conserved phosphorylation site His(552) residue or the phosphorelay site Asp(989) residue had been replaced failed to complement the sln1-ts mutant. In addition, introduction of the tcsB cDNA into an s1n1Delta sho1Delta yeast double mutant, which lacked two osmosensors, suppressed lethality in high-salinity media and activated the HOG1 MAPK. These results imply that TcsB functions as an osmosensor histidine kinase. We constructed an A. nidulans strain lacking the tcsB gene (tcsBDelta) and examined its phenotype. However, unexpectedly, the tcsBDelta strain did not exhibit a detectable phenotype for either hyphal development or morphology on standard or stress media. Our results suggest that A. nidulans has more complex and robust osmoregulatory systems than the yeast SLN1-HOG1 MAPK cascade.