Neutral trehalases catalyse intracellular trehalose breakdown in the filamentous fungi Aspergillus nidulans and Neurospora crassa
Neutral trehalases catalyse intracellular trehalose breakdown in the filamentous fungi Aspergillus nidulans and Neurospora crassa
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DOI：
10.1046/j.1365-2958.1999.01327.x
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发表时间：
1999-05-01
影响因子：
3.6
通讯作者：
Terenzi, HF
中科院分区：
文献类型：
--
作者：
d'Enfert, C;Bonini, BM;Terenzi, HF
在构巢曲霉和粗糙脉孢菌的萌发分生孢子中鉴定出 cAMP 可激活的 Ca2+ 依赖性中性海藻糖酶。使用 PCR 方法，对编码几种酵母中发现的中性海藻糖酶同源物的构巢曲霉和粗糙脉孢菌基因进行了克隆和测序。编码构巢曲霉中性海藻糖酶的 AntreB 基因的破坏表明，它负责分生孢子萌发开始时的细胞内海藻糖动员，并且这种现象部分参与萌发分生孢子中甘油的瞬时积累，尽管海藻糖动员对于完成孢子萌发和丝状生长并不是必需的。 对于构巢菌，需要在碳限制下达到野生型萌发率，这表明细胞内海藻糖可以部分贡献孢子萌发的能量需求。此外，研究表明构巢曲霉中海藻糖的积累可以保护正在发芽的分生孢子免受致命的热休克。由于treB基因的转录在热休克后不会增加，而是在热休克恢复时诱导，因此有人提出，在丝状真菌中，转录和翻译后调节机制，特别是cAMP依赖性蛋白激酶介导的磷酸化，会促进恢复适当生长期间海藻糖的动员。
A cAMP-activatable Ca2+-dependent neutral trehalase was identified in germinating conidia of Aspergillus nidulans and Neurospora crassa. Using a PCR approach, A. nidulans and N. crassa genes encoding homologues of the neutral trehalases found in several yeasts were cloned and sequenced. Disruption of the AntreB gene encoding A. nidulans neutral trehalase revealed that it is responsible for intracellular trehalose mobilization at the onset of conidial germination, and that this phenomenon is partially involved in the transient accumulation of glycerol in the germinating conidia, Although trehalose mobilization is not essential for the completion of spore germination and filamentous growth in A. nidulans, it is required to achieve wild-type germination rates under carbon limitation, suggesting that intracellular trehalose can partially contribute the energy requirements of spore germination. Furthermore, it was shown that trehalose accumulation in A. nidulans can protect germinating conidia against an otherwise lethal heat shock. Because transcription of the treB genes is not increased after a heat shock but induced upon heat shock recovery, it is proposed that, in filamentous fungi, mobilization of trehalose during the return to appropriate growth is promoted by transcriptional and post-translational regulatory mechanisms, in particular cAMP-dependent protein kinase-mediated phosphorylation.