Regulation of cyclic peptide biosynthesis in a plant pathogenic fungus by a novel transcription factor
Regulation of cyclic peptide biosynthesis in a plant pathogenic fungus by a novel transcription factor
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DOI：
10.1073/pnas.231491298
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发表时间：
2001-11-20
影响因子：
11.1
通讯作者：
Walton, JD
中科院分区：
文献类型：
--
作者：
Pedley, KF;Walton, JD
丝状真菌Cochliobolus carbonum的菌株产生宿主选择性化合物HC-毒素，一种环状四肽，对某些基因型的玉米（Zea mays L.）具有高毒性。HC毒素的产生受一个复杂的基因座TOX2的控制，该基因座由至少7个连锁和重复的基因组成，这些基因仅存在于产毒素的C.碳。这些基因中的一个，TOXE，早先被证明是其它TOX2基因表达所必需的。TOXE有四个锚蛋白重复序列和一个类似于碱性亮氨酸拉链（bZIP）蛋白的碱性区域，但缺乏任何明显的亮氨酸拉链。在这里，我们表明，TOXE是一种DNA结合蛋白，它识别一个10个碱基的基序（“毒盒”）没有二分体对称性，是目前在所有已知的TOX2基因的启动子。碱性区和锚蛋白重复序列都参与DNA结合。一个区域的TOXE，包括第一个锚蛋白重复是必要的，足以在酵母中的转录激活。这些数据表明，TOXE是一个新的转录因子家族的原型，到目前为止只在植物病原真菌中发现。TOXE在HC毒素的产生中起着特异性的调节作用，因此，它对C.碳。
Strains of the filamentous fungus Cochliobolus carbonum that produce the host-selective compound HC-toxin, a cyclic tetrapeptide, are highly virulent on certain genotypes of maize (Zea mays L.). Production of HC-toxin is under the control of a complex locus, TOX2, which is composed of at least seven linked and duplicated genes that are present only in toxin-producing strains of C. carbonum. one of these genes, TOXE, was earlier shown to be required for the expression of the other TOX2 genes. TOXE has four ankyrin repeats and a basic region similar to those found in basic leucine zipper (bZIP) proteins, but lacks any apparent leucine zipper. Here we show that TOXE is a DNA-binding protein that recognizes a ten-base motif (the "tox-box") without dyad symmetry that is present in the promoters of all of the known TOX2 genes. Both the basic region and the ankyrin repeats are involved in DNA binding. A region of TOXE that includes the first ankyrin repeat is necessary and sufficient for transcriptional activation in yeast. The data indicate that TOXE is the prototype of a new family of transcription factor, so far found only in plant-pathogenic fungi. TOXE plays a specific regulatory role in HC-toxin production and, therefore, pathogenicity by C. carbonum.