The cell surface flocculin Flo11 is required for pseudohyphae formation and invasion by Saccharomyces cerevisiae
The cell surface flocculin Flo11 is required for pseudohyphae formation and invasion by Saccharomyces cerevisiae
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DOI：
10.1091/mbc.9.1.161
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发表时间：
1998-01-01
影响因子：
3.3
通讯作者：
Dranginis, AM
中科院分区：
文献类型：
--
作者：
Lo, WS;Dranginis, AM
二倍体酵母在氮饥饿时产生假菌丝，而单倍体酵母在丰富培养基中产生侵入性丝状体，其穿透琼脂。我们已经确定了一个基因，FLO 11，编码细胞壁蛋白，这是至关重要的入侵和假菌丝形成响应氮饥饿。FLO 11编码一种细胞表面絮凝蛋白，其结构类似于富含丝氨酸/苏氨酸的酵母GPI锚定细胞壁蛋白。缺失FLO 11的酿酒酵母菌株Sigma 1278 b的细胞不形成假菌丝作为二倍体，也不侵入琼脂作为单倍体。在丰富的培养基中，FLO 11受交配类型调节;它在单倍体细胞中表达，但不在二倍体中表达。然而，当转移到氮饥饿培养基中时，FLO 11转录物在二倍体细胞中积累，但不在单倍体中积累。FLO 11在二倍体细胞中的过表达，使它们能够侵入琼脂，否则这些细胞是不具有侵袭性的。因此，在丰富培养基中生长的二倍体中FLO 11的交配型阻遏足以解释这些细胞不能侵入。FLO 11的启动子包含Ste 12 p和Tec 1 p的共有结合序列，已知这些蛋白质在假菌丝发育期间协同激活Ty 1元件和TEC 1基因的转录。STE 12缺失的酵母不表达FLO 11转录本，表明STE 12是FLO 11表达所必需的。这些ste 12缺失菌株也不侵入琼脂。然而，入侵能力可以通过过表达FLO 11来恢复。因此，FLO 11的激活可能是Ste 12 p和Tec 1 p引起侵入性生长的主要手段。
Diploid yeast develop pseudohyphae in response to nitrogen starvation, while haploid yeast produce invasive filaments which penetrate the agar in rich medium. We have identified a gene, FLO11, that-encodes a cell wall protein which is critically required for both invasion and pseudohyphae formation in response to nitrogen starvation. FLO11 encodes a cell surface flocculin with a structure similar to the class of yeast serine/threonine-rich GPI-anchored cell wall proteins. Cells of the Saccharomyces cerevisiae strain Sigma 1278b with deletions of FLO11 do not form pseudohyphae as diploids nor invade agar as haploids. In rich media, FLO11 is regulated by mating type; it is expressed in haploid cells but not in diploids. Upon transfer to nitrogen starvation media, however, FLO11 transcripts accumulate in diploid cells, but not in haploids. Overexpression of FLO11 in diploid cells, which are otherwise not invasive, enables them to invade agar. Thus, the mating type repression of FLO11 in diploids grown in rich media suffices to explain the inability of these cells to invade. The promoter of FLO11 contains a consensus binding sequence for Ste12p and Tec1p, proteins known to cooperatively activate transcription of Ty1 elements and the TEC1 gene during development of pseudohyphae. Yeast with a deletion of STE12 does not express FLO11 transcripts, indicating that STE12 is required for FLO11 expression. These ste12-deletion strains also do not invade agar. However, the ability to invade can be restored by overexpressing FLO11. Activation of FLO11 may thus be the primary means by which Ste12p and Tec1p cause invasive growth.