Department of Biomolecular Chemistry, University of Wisconsin, School of Medicine and Public Health, Madison, WI 53706, United States.
Fungal Genet Biol. 2010 Apr;47(4):310-7. doi: 10.1016/j.fgb.2009.12.010. Epub 2010 Jan 4.
During sexual development the human fungal pathogen Cryptococcus neoformans undergoes a developmental transition from yeast-form growth to filamentous growth. This transition requires cellular restructuring to form a filamentous dikaryon. Dikaryotic growth also requires tightly controlled nuclear migration to ensure faithful replication and dissemination of genetic material to spore progeny. Although the gross morphological changes that take place during dikaryotic growth are largely known, the molecular underpinnings that control this process are uncharacterized. Here we identify and characterize a C. neoformans homolog of the Saccharomyces cerevisiae BIM1 gene, and establish the importance of BIM1 for proper filamentous growth of C. neoformans. Deletion of BIM1 leads to truncated sexual development filaments, a severe defect in diploid formation, and a block in monokaryotic fruiting. Our findings lead to a model consistent with a critical role for BIM1 in both filament integrity and nuclear congression that is mediated through the microtubule cytoskeleton.
在性发育过程中，人类真菌病原体新型隐球菌经历了从酵母形态生长到丝状生长的发育转变。这种转变需要细胞结构的重新构建，以形成丝状双核体。双核体的生长还需要严格控制核迁移，以确保遗传物质的准确复制和传播到孢子后代。尽管在双核体生长过程中发生的宏观形态变化在很大程度上是已知的，但控制这一过程的分子基础尚未确定。在这里，我们鉴定并表征了新型隐球菌与酿酒酵母 BIM1 基因的同源物，并确定了 BIM1 对新型隐球菌正确丝状生长的重要性。BIM1 的缺失导致性发育丝状结构截断，二倍体形成严重缺陷，以及单核果形成受阻。我们的研究结果提出了一个模型，该模型一致认为 BIM1 在丝状完整性和核聚集中起关键作用，这是通过微管细胞骨架介导的。
