Microbiology and Kluyver Centre for Genomics of Industrial Fermentations, Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, the Netherlands.
Environ Microbiol. 2010 Apr;12(4):833-44. doi: 10.1111/j.1462-2920.2009.02122.x. Epub 2009 Dec 27.
Mushroom-forming basidiomycetes colonize large areas in nature. Their hyphae are compartmentalized by perforated septa, which are usually covered by a septal pore cap (SPC). Here, we describe, for the first time, the composition and function of SPCs using the model system Schizophyllum commune. The SPC of S. commune was shown to consist of a proteinaceous matrix covered by a lipid membrane. The matrix was demonstrated to define the ultrastructure of the SPC and to consist of two main proteins, Spc14 and Spc33. Gene spc14 encodes a protein of 86 amino acids, which lacks known domain, signal or localization sequences. Gene spc33 encodes a 239 and a 340 amino acid variant. Both forms contain a predicted signal anchor that targets them to the ER. Immuno-localization showed the presence of Spc33 in the SPC but not in ER. From this and previous reports it is concluded that the SPC is derived from this organelle. Inactivation of spc33 resulted in loss of SPCs and the inability to close septa. The latter may well explain why vegetative growth and mushroom formation were severely reduced in strains in which spc33 was inactivated.
担子菌类真菌在自然界中大面积定殖。它们的菌丝被有孔隔膜分隔，这些隔膜通常被隔膜孔盖（SPC）覆盖。在这里，我们首次使用模型系统 Schizophyllum commune 描述了 SPC 的组成和功能。S. commune 的 SPC 由蛋白质基质组成，上面覆盖有脂质膜。基质决定了 SPC 的超微结构，由两种主要蛋白质 Spc14 和 Spc33 组成。spc14 基因编码一个由 86 个氨基酸组成的蛋白质，缺乏已知的结构域、信号或定位序列。spc33 基因编码一个 239 个和一个 340 个氨基酸的变体。这两种形式都包含一个预测的信号锚，将它们靶向 ER。免疫定位显示 Spc33 存在于 SPC 中，但不存在于 ER 中。从这一点和以前的报道可以得出结论，SPC 是从这个细胞器衍生而来的。spc33 的失活导致 SPC 的丧失和隔膜无法关闭。这可能很好地解释了为什么 spc33 失活的菌株的营养生长和蘑菇形成严重减少。
