TRANSCRIPTION OF THE GENE FOR A PEPSINOGEN, PEP1, IS REGULATED BY WHITE-OPAQUE SWITCHING IN CANDIDA-ALBICANS
TRANSCRIPTION OF THE GENE FOR A PEPSINOGEN, PEP1, IS REGULATED BY WHITE-OPAQUE SWITCHING IN CANDIDA-ALBICANS
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DOI：
10.1128/mcb.12.7.2997
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发表时间：
1992-07-01
影响因子：
5.3
通讯作者：
SOLL, DR
中科院分区：
文献类型：
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作者：
MORROW, B;SRIKANTHA, T;SOLL, DR
白色念珠菌WO-1的细胞自发地在白色和不透明CFU之间转换，并且这种相变涉及细胞表型的显著变化。通过使用差异杂交筛选，不透明的特异性cDNA，Opla，它代表的转录本的基因调节开关，已被分离。Opla的基因在不透明细胞中转录，但在白色细胞中不转录。Opla cDNA序列与C.预测的氨基酸序列表明该基因的产物是胃蛋白酶原家族的成员，其具有用于分泌的疏水前导序列和两个催化天冬氨酸结构域。用14种不同的核酸内切酶消化两种基因组DNA并用电泳分离的染色体，用Opla cDNA进行Southern印迹。在白色和不透明细胞之间的任何一种情况下都没有检测到多态性，这表明在白色-不透明过渡期间基因附近没有发生基因组重组。尽管Opla的转录与不透明细胞培养物中高水平的胞外蛋白酶活性和白色细胞培养物中无活性相关，但在WO-1白色细胞培养物或另外两种临床分离的念珠菌培养物中，通过加入血清白蛋白刺激胞外蛋白酶活性并不伴随Opla转录。白色念珠菌，表明在这些情况下刺激一种或多种其他蛋白酶基因的表达。结果表明，在WO-1菌株中，Opla基因的转录受到开关的严格控制。
Cells of Candida albicans WO-1 spontaneously switch between a white and opaque CFU, and this phase transition involves a dramatic change in cellular phenotype. By using a differential hybridization screen, an opaque-specific cDNA, Opla, which represents the transcript of a gene regulated by switching, has been isolated. The gene for Opla is transcribed by opaque but not by white cells. The nucleotide sequence of the Opla cDNA reveals over 99% base homology with an acid protease gene of C. albicans, and the predicted amino acid sequence demonstrates that the product of this gene is a member of the family of pepsinogens, which possess a hydrophobic leader sequence for secretion and two catalytic aspartate domains. Southern blots of both genomic DNA digested with 14 different endonucleases and electrophoretically separated chromosomes were probed with the Opla cDNA. No polymorphisms were detected in either case between white and opaque cells, suggesting that no genomic reorganization occurs in the proximity of the gene during the white-opaque transition. Although transcription of Opla correlates with the high levels of extracellular protease activity in opaque cell cultures and the absence of activity in white cell cultures, stimulation of extracellular protease activity by addition of serum albumin is not accompanied by Opla transcription in cultures of WO-1 white cells or cultures of two additional clinical isolates of C. albicans, suggesting that expression of one or more other protease genes is stimulated in these cases. The results demonstrate that transcription of the Opla gene is under the rigid control of switching in strain WO-1.