Spontaneous second-site suppressors of the filamentation defect of prr1Delta mutants define a critical domain of Rim101p in Candida albicans.
Spontaneous second-site suppressors of the filamentation defect of prr1Delta mutants define a critical domain of Rim101p in Candida albicans.
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prr1Delta 突变体丝状化缺陷的自发第二位点抑制因子定义了白色念珠菌中 Rim101p 的关键结构域。
DOI：
10.1007/s004380100581
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Fonzi,WA
中科院分区：
文献类型：
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作者：
Porta,A;Wang,Z;Ramon,A;Muhlschlegel,FA;Fonzi,WA
为了响应环境 pH 值的变化，机会性病原体白色念珠菌差异性地表达许多基因。对 pH 值的反应影响形态分化和毒力。控制 pH 响应的途径终止于含有 RIM101/PRR2 编码的转录因子的锌指。类比构巢曲霉的pH响应途径，PRR1 of C. albicansen 编码一种蛋白质，可能需要通过蛋白水解去除 C 端肽将 Rim101p 从无活性形式转化为活性形式。 Aprr1Δ突变体分化成丝状形式的能力受到损害。 aprr1Δ突变体的自发表型回复体根据其形成丝状菌落的能力进行选择。这些突变体还被发现在 pH 依赖性基因表达方面存在缺陷。检查的八个突变体中的每一个都在 RIM101 基因座上含有杂合显性突变。这在所有突变体中得到了遗传证明，并通过两个突变体中两个等位基因的序列测定直接得到了证实。突变等位基因赋予 aprr1Δ 突变体成丝的能力，从而证明它们直接负责抑制成丝缺陷。七个突变等位基因包含 1 个 bp 取代，一个在相邻位置包含两个取代。这些突变聚集在基因 3' 端附近的 90 bp 区域内。在所有情况下，突变都会产生无义密码子，导致 Rim101p 过早终止；突变蛋白被截短了 75-104 个氨基酸。结果定义了 Rim101p C 末端区域的关键区域，并且与所提出的 Rim101p 蛋白水解激活一致。
In response to changes in ambient pH the opportunistic pathogenCandida albicansdifferentially expresses a number of genes. The response to pH affects morphological differentiation and virulence. The pathway controlling the pH response terminates in the zinc-finger containing transcription factor encoded byRIM101/PRR2. By analogy to the pH response pathway ofAspergillus nidulans,PRR1ofC. albicansencodes a protein that is presumably required to convert Rim101p from an inactive to an active form by proteolytic removal of a C-terminal peptide. Aprr1Δ mutant is compromised in its ability to differentiate into the filamentous form. Spontaneous phenotypic revertants of aprr1Δ mutant were selected by their ability to form filamentous colonies. These mutants were also found to be defective in pH-dependent gene expression. Each of the eight mutants examined contained a heterozygous dominant mutation at theRIM101locus. This was demonstrated genetically in all of the mutants, and directly by sequence determination of both alleles in two of the mutants. The mutant alleles conferred the ability to filament to aprr1Δ mutant, thus demonstrating that they were directly responsible for suppressing the filamentation defect. Seven of the mutant alleles contained a 1-bp substitution and one contained two substitutions at adjacent positions. The mutations were clustered within a 90-bp region near the 3′-end of the gene. In all cases the mutation generated a nonsense codon that resulted in premature termination of Rim101p; the mutant proteins were truncated by 75–104 amino acids. The results define a critical region in the C-terminal region of Rim101p and are consistent with the proposed proteolytic activation of Rim101p.