POSSIBLE MECHANISM FOR FLOCCULATION INTERACTIONS GOVERNED BY GENE FLO1 IN SACCHAROMYCES-CEREVISIAE
POSSIBLE MECHANISM FOR FLOCCULATION INTERACTIONS GOVERNED BY GENE FLO1 IN SACCHAROMYCES-CEREVISIAE
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DOI：
10.1128/jb.150.2.878-889.1982
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发表时间：
1982-01-01
影响因子：
3.2
通讯作者：
SELIGY, VL
中科院分区：
文献类型：
--
作者：
MIKI, BLA;POON, NH;SELIGY, VL
提出了酵母中絮凝相互作用机制的模型，其中絮凝细胞具有附着于α-其他细胞上的甘露聚糖位点。这一因素可能是由单显性基因FLO 1的表达控制的。S.酿酒酵母，不同的只是在FLO 1和标记基因ade 1和trp 1，被开发来检查参与絮凝的成分。EM和伴刀豆球蛋白A-铁蛋白标记的聚集细胞表明，广泛和强烈的细胞壁甘露聚糖层介导的细胞聚集之间的相互作用。絮凝所必需的甘露聚糖层的组分是Ca 2+离子，α-甘露聚糖碳水化合物和蛋白质。通过研究二价阳离子依赖性在不同的pH值和在竞争的一价阳离子的存在下，絮凝被发现是Ca 2+依赖性的;然而，Mg 2+和Mn 2+离子取代Ca 2+在某些条件下。伴刀豆球蛋白A和琥珀酰化伴刀豆球蛋白A对絮凝的可逆抑制涉及α-支链甘露聚糖碳水化合物作为一种基本组分，其单独不能决定絮凝的菌株特异性，因为非絮凝菌株与絮凝细胞相互作用并竞争絮凝细胞上的结合位点。FLO 1可以支配蛋白质的凝集素样活性的表达，其与絮状细胞的细胞壁牢固地结合，所述絮状细胞结合α-邻接细胞的甘露聚糖碳水化合物。通过蛋白质水解和二硫键的还原，它被选择性地和不可逆地抑制。这个系统作为一个模型的遗传和生物化学控制的细胞-细胞相互作用的潜力进行了讨论。
A model is proposed for the mechanism of flocculation interactions in yeasts in which flocculent cells have a recognition factor which attaches to .alpha.-mannan sites on other cells. This factor may be governed by the expression of the single dominant gene FLO1. Isogenic strains of S. cerevisiae, differing only at FLO1 and the marker genes ade1 and trp1, were developed to examine the components involved in flocculence. EM and concanavalin A-ferritin labeling of aggregated cells showed that extensive and intense interactions between cell wall mannan layers mediated cell aggregation. The components of the mannan layer essential for flocculence were Ca2+ ions, .alpha.-mannan carbohydrates and proteins. By studying the divalent cation dependence at various pH values and in the presence of competing monovalent cations, flocculation was found to be Ca2+ dependent; however, Mg2+ and Mn2+ ions substituted for Ca2+ under certain conditions. Reversible inhibition of flocculation by concanavalin A and succinylated concanavalin A implicated .alpha.-branched mannan carbohydrates as one essential component which alone did not determine the strain specificity of flocculence, since nonflocculent strains interacted with and competed for binding sites on flocculent cells. FLO1 may govern the expression of a proteinaceous, lectin-like activity, firmly associated with the cell walls of flocculent cells, which bind to the .alpha.-mannan carbohydrates of adjoining cells. It was selectively and irreversibly inhibited by proteolysis and reduction of disulfide bonds. The potential of this system as a model for the genetic and biochemical control of cell-cell interactions is discussed.