Oh Soon-Hwan, Isenhower Allyson, Rodriguez-Bobadilla Rubi, Smith Brooke, Jones Jillian, Hubka Vit, Fields Christopher, Hernandez Alvaro, Hoyer Lois L
Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, United States.
Department of Biology, Millikin University, Decatur, IL, United States.
Front Microbiol. 2021 Jan 20;11:594531. doi: 10.3389/fmicb.2020.594531. eCollection 2020.
The agglutinin-like sequence () gene family encodes cell-surface adhesins that interact with host and abiotic surfaces, promoting colonization by opportunistic fungal pathogens such as . Studies of Als protein contribution to adhesion would benefit from an accurate catalog of gene sequences as well as insight into relative gene expression levels. Even in the genomics era, this information has been elusive: genome assemblies are often broken within genes because of their extensive regions of highly conserved, repeated DNA sequences and because there are many similar genes at different chromosomal locations. Here, we describe the benefit of long-read DNA sequencing technology to facilitate characterization of loci. Thirteen loci in strain MYA-3404 were deduced from a genome assembly constructed from Illumina MiSeq and Oxford Nanopore MinION data. Although the MinION data were valuable, PCR amplification and Sanger sequencing of loci were still required to complete and verify the gene sequences. Each predicted Als protein featured an N-terminal binding domain, a central domain of tandemly repeated sequences, and a C-terminal domain rich in Ser and Thr. The presence of a secretory signal peptide and consensus sequence for addition of a glycosylphosphatidylinositol (GPI) anchor was consistent with predicted protein localization to the cell surface. TaqMan assays were designed to recognize each gene, as well as both alleles at the divergent locus. cells grown in five different conditions showed differential expression of various genes. To place the data into a larger context, TaqMan assays were also designed and validated for analysis of gene expression in and . These comparisons identified the subset of highly expressed genes that were predicted to encode proteins with the most abundant cell-surface presence, prioritizing them for subsequent functional analysis. Data presented here provide a solid foundation for future experimentation to deduce family contributions to adhesion and pathogenesis.
类凝集素序列(Als)基因家族编码与宿主和非生物表面相互作用的细胞表面粘附素,促进白色念珠菌等机会性真菌病原体的定殖。研究Als蛋白对白色念珠菌粘附的作用将受益于Als基因序列的准确目录以及对相对基因表达水平的深入了解。即使在基因组学时代,这些信息也难以捉摸:由于其高度保守的重复DNA序列区域广泛,并且在不同染色体位置存在许多相似的Als基因,基因组组装通常在Als基因内中断。在这里,我们描述了长读长DNA测序技术在促进Als基因座表征方面的优势。从由Illumina MiSeq和Oxford Nanopore MinION数据构建的基因组组装中推断出白色念珠菌菌株MYA-3404中的13个Als基因座。尽管MinION数据很有价值,但仍需要对Als基因座进行PCR扩增和桑格测序以完成和验证基因序列。每个预测的Als蛋白都具有一个N端结合结构域、一个串联重复序列的中央结构域和一个富含丝氨酸和苏氨酸的C端结构域。分泌信号肽的存在以及添加糖基磷脂酰肌醇(GPI)锚的共有序列与预测的蛋白定位于细胞表面一致。设计了TaqMan分析来识别每个Als基因以及在不同的Als位点上的两个等位基因。在五种不同生长条件下培养的白色念珠菌细胞显示出各种Als基因的差异表达。为了将白色念珠菌的数据置于更大的背景中,还设计并验证了TaqMan分析以分析热带念珠菌和光滑念珠菌中的Als基因表达。这些比较确定了预测编码细胞表面存在最丰富的蛋白的高表达Als基因子集,优先对它们进行后续功能分析。本文提供的数据为未来推断Als家族对白色念珠菌粘附和发病机制的作用的实验奠定了坚实的基础。