A Rac homolog is required for induction of hyphal growth in the dimorphic yeast Yarrowia lipolytica
A Rac homolog is required for induction of hyphal growth in the dimorphic yeast Yarrowia lipolytica
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DOI：
10.1128/jb.182.9.2376-2386.2000
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发表时间：
2000-05-01
影响因子：
3.2
通讯作者：
Rachubinski, RA
中科院分区：
文献类型：
--
作者：
Hurtado, CAR;Beckerich, JM;Rachubinski, RA
人们认为真菌中的二态性构成了对不利条件的反应机制，并且代表了许多病原真菌物种毒力发展的重要属性。我们分离出了 YlR-AC1，这是一种编码 192 个氨基酸蛋白质的基因，该蛋白质对于二态性酵母解脂耶氏酵母的菌丝生长至关重要，并且代表了迄今为止真菌描述的第一个 Rac 同源物。 YlRAC1 不是必需基因，其缺失不会影响解脂耶氏酵母的交配能力或损害肌动蛋白极化。然而，缺乏功能性 YlRAC1 的菌株显示出细胞形态的改变，表明 YlRAC1 的功能可能与细胞生长极化的某些方面有关。 Northern 印迹分析表明，YlRAC1 的转录在酵母向菌丝转变过程中稳定增加，而基因组 DNA 的 Southern 印迹分析表明解脂耶氏酵母中存在多个 RAC 家族成员。有趣的是，缺乏功能性YlRAC1的菌株仍然能够以假菌丝形式生长并侵入琼脂，因此表明YlRAC1在MHY1下游具有功能，MHY1是先前分离的编码C2W2型锌指蛋白的基因，能够结合推定的应激反应元件，其活性对于解脂耶氏酵母中的菌丝和假菌丝生长至关重要。
Dimorphism in fungi is believed to constitute a mechanism of response to adverse conditions and represents an important attribute for the development of virulence by a number of pathogenic fungal species. We have isolated YlR-AC1, a gene encoding a 192-amino-acid protein that is essential for hyphal growth in the dimorphic yeast Yarrowia lipolytica and which represents the first Rac homolog described far fungi. YlRAC1 is not an essential gene, and its deletion does not affect the ability to mate or impair actin polarization in Y. lipolytica. However, strains lacking functional YlRAC1 show alterations in cell morphology suggesting that the function of YlRAC1 may be related to some aspect of the polarization of cell growth. Northern blot analysis show ed that transcription of YlRAC1 increases steadily during the yeast-to-hypha transition, while Southern blot analysis of genomic DNA suggested the presence of several RAC family members in Y. lipolytica. Interestingly, strains lacking functional YlRAC1 are still able to grow as the pseudohyphal form and to invade agar, thus pointing to a function for YlRAC1 downstream of MHY1, a previously isolated gene encoding a C2W2 type zinc finger protein with the ability to bind putative stress response elements and whose activity is essential for both hyphal and pseudohyphal growth in Y. lipolytica.