Finney R, Langtimm C J, Soll D R
Mycopathologia. 1985 Jul;91(1):3-15. doi: 10.1007/BF00437280.
Under the regime of pH-regulated dimorphism, stationary phase cells of the dimorphic yeast Candida albicans can be induced to form exclusively and synchronously ellipsoidal buds or elongate mycelia at the same temperature and in the same nutrient medium, the sole determinant of phenotype in this case being pH. Employing pH-regulated dimorphism, cells were pulse-labeled with [35S]-methionine during three consecutive intervals encompassing the preevagination period, the period including evagination and phenotypic commitment, and the post-evagination period. Labeled polypeptides were analyzed by 2D-PAGE. Of the 374 polypeptides examined, the majority (237) did not differ significantly in relative incorporation between the three pulse periods and were similar between budding and mycelium-forming populations. Sixty polypeptides were labeled at negligible or relatively low levels during the first pulse period, but at significantly higher levels during the second and third or third pulse periods. All but one were similar between budding and mycelium-forming populations. Seventeen polypeptides were synthesized at relatively high levels during the first pulse period, but at reduced or negligible levels during the second and third or third pulse periods. All but one were similar between budding and mycelium-forming populations. Only two polypeptides were found to be associated exclusively with mycelium-forming cultures, two associated exclusively with budding cultures, and two enriched significantly in budding cultures of wild-type cells. Employing a variant, MD20, which forms buds at both low and high pH, it was demonstrated that only one mycelium-associated polypeptide and only one bud-associated polypeptide are phenotype rather than pH-specific. Limits to this method of phenotype comparison are outlined, and the unusual similarity rather than dissimilarity in the programs of gene expression between the diverging populations considered in terms of phenotypic regulation.
在pH调节的双态性机制下，双态酵母白色念珠菌的稳定期细胞可以在相同温度和相同营养培养基中被诱导仅同步形成椭圆形芽或伸长的菌丝体，在这种情况下，表型的唯一决定因素是pH。利用pH调节的双态性，在包括预出芽期、包括出芽和表型确定期以及出芽后期的三个连续时间段内，用[35S] - 甲硫氨酸对细胞进行脉冲标记。通过二维聚丙烯酰胺凝胶电泳分析标记的多肽。在所检测的374种多肽中，大多数（237种）在三个脉冲期之间的相对掺入量没有显著差异，并且在芽殖群体和菌丝体形成群体之间相似。60种多肽在第一个脉冲期标记水平可忽略不计或相对较低，但在第二个和第三个或第三个脉冲期显著升高。除一种外，所有这些在芽殖群体和菌丝体形成群体之间都相似。17种多肽在第一个脉冲期以相对较高的水平合成，但在第二个和第三个或第三个脉冲期水平降低或可忽略不计。除一种外，所有这些在芽殖群体和菌丝体形成群体之间都相似。仅发现两种多肽仅与菌丝体形成培养物相关，两种仅与芽殖培养物相关，两种在野生型细胞的芽殖培养物中显著富集。利用在低pH和高pH下都形成芽的变体MD20，证明只有一种与菌丝体相关的多肽和一种与芽相关的多肽是表型特异性而非pH特异性的。概述了这种表型比较方法的局限性，并从表型调节的角度考虑了不同群体之间基因表达程序中不寻常的相似性而非差异性。
