Kasuga Takao, Glass N Louise
Department of Plant Pathology, University of California, Berkeley, Berkeley, CA 95616, USA.
Eukaryot Cell. 2008 Sep;7(9):1549-64. doi: 10.1128/EC.00195-08. Epub 2008 Aug 1.
Colony development, which includes hyphal extension, branching, anastomosis, and asexual sporulation, is a fundamental aspect of the life cycle of filamentous fungi; genetic mechanisms underlying these phenomena are poorly understood. We conducted transcriptional profiling during colony development of the model filamentous fungus Neurospora crassa, using 70-mer oligonucleotide microarrays. Relative mRNA expression levels were determined for six sections of defined age excised from a 27-h-old N. crassa colony. Functional category analysis showed that the expression of genes involved in cell membrane biosynthesis, polar growth, and cellular signaling was enriched at the periphery of the colony. The relative expression of genes involved in protein synthesis and energy production was enriched in the middle section of the colony, while sections of the colony undergoing asexual development (conidiogenesis) were enriched in expression of genes involved in protein/peptide degradation and unclassified proteins. A cross-examination of the N. crassa data set with a published data set of Aspergillus niger revealed shared patterns in the spatiotemporal regulation of gene orthologs during colony development. At present, less than 50% of genes in N. crassa have functional annotation, which imposes the chief limitation on data analysis. Using an evolutionary approach, we observed that the expression of phylogenetically conserved groups of genes was enriched in the middle section of an N. crassa colony whereas expression of genes unique to euascomycete species and of N. crassa orphan genes was enriched at the colony periphery and in the older, conidiating sections of a fungal colony.
菌落发育包括菌丝延伸、分支、吻合以及无性孢子形成,是丝状真菌生命周期的一个基本方面;但这些现象背后的遗传机制却鲜为人知。我们使用70聚体寡核苷酸微阵列,在模式丝状真菌粗糙脉孢菌的菌落发育过程中进行了转录谱分析。测定了从一个27小时龄的粗糙脉孢菌菌落切下的六个特定年龄切片中的相对mRNA表达水平。功能类别分析表明,参与细胞膜生物合成、极性生长和细胞信号传导的基因表达在菌落边缘富集。参与蛋白质合成和能量产生的基因的相对表达在菌落中部富集,而经历无性发育(分生孢子形成)的菌落切片中,参与蛋白质/肽降解的基因和未分类蛋白质的基因表达富集。将粗糙脉孢菌的数据集与已发表的黑曲霉数据集进行交叉检验,发现在菌落发育过程中基因直系同源物的时空调控存在共同模式。目前,粗糙脉孢菌中不到50%的基因有功能注释,这对数据分析造成了主要限制。通过进化方法,我们观察到,系统发育保守基因群的表达在粗糙脉孢菌菌落中部富集,而子囊菌物种特有的基因和粗糙脉孢菌孤儿基因的表达在菌落边缘以及真菌菌落较老的产分生孢子区域富集。