Candida albicans sfl1 suppresses flocculation and filamentation
Candida albicans sfl1 suppresses flocculation and filamentation
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DOI：
10.1128/ec.00236-07
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发表时间：
2007-10-01
期刊：
影响因子：
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通讯作者：
Wendland, Juergen
中科院分区：
文献类型：
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作者：
Bauer, Janine;Wendland, Juergen
白色念珠菌菌丝的形态发生受多种途径的调控，这些途径可以诱导或抑制菌丝的形成。最值得注意的是，Tup1、Nrg1和Rfg1是转录抑制因子，而Efg1、Flo8、Cph1和Czf1可以诱导成丝。在此，我们对编码酿酒酵母SFL1（絮凝抑制基因）的白色念珠菌同源基因的CaSFL1进行了功能分析。CaSFL1的缺失导致酵母细胞絮凝（即形成团块），这在最小培养基中最为明显。这些絮凝体已经在非诱导条件下含有菌丝，在37℃的条件下，菌丝诱导可以增强。在CaMET3启动子控制下的杂合突变体中，SFL1的表达可以弥补这些缺陷，并允许在野生型和突变型之间切换。有趣的是，在诱导成丝之前，使用MET3prom-SFL1构建体增加SFL1的表达完全阻断了胚管的形成。为了在体内定位Sfl1，我们构建了Sfl1 - gfp融合。在酵母细胞和菌丝细胞的细胞核中都发现了sfl1绿色荧光蛋白，在较小程度上也发现了。通过逆转录- pcr，我们发现ALS1、ALS3、HWP1、ECE1和FLO8的表达增加。我们的研究结果表明，Sfl1在抑制絮凝和丝化中起作用，因此代表了白色念珠菌形态发生的一种新的负调控因子。
Hyphal morphogenesis in Candida albicans is regulated by multiple pathways which act by either inducing or repressing filamentation. Most notably, Tup1, Nrg1, and Rfg1 are transcriptional repressors, while Efg1, Flo8, Cph1, and Czf1 can induce filamentation. Here, we present the functional analysis of CaSFL1, which encodes the C. albicans homolog of the Saccharomyces cerevisiae SFL1 (suppressor of flocculation) gene. Deletion of CaSFL1 results in flocculation (i.e., the formation of clumps) of yeast cells, which is most pronounced in minimal medium. The flocs contained hyphae already under noninducing conditions, and filamentation could be enhanced with hypha-inducing cues at 37 degrees C. Expression of SFL1 in a heterozygous mutant under the control of the CaMET3 promoter was shown to complement these defects and allowed switching between wild-type and mutant phenotypes. Interestingly, increased expression of SFL1 using a MET3prom-SFL1 construct prior to the induction of filamentation completely blocked germ tube formation. To localize Sfl1 in vivo, we generated a SFL1-GFP fusion. Sfl1-green fluorescent protein was found in the nucleus in both yeast cells and, to a lesser extent, hyphal cells. Using reverse transcription-PCR, we find an increased expression of ALS1, ALS3, HWP1, ECE1, and also FLO8. Our results suggest that Sfl1 functions in the repression of flocculation and filamentation and thus represents a novel negative regulator of C. albicans morphogenesis.