标题：Aspergillus fumigatus flbB encodes two basic leucine zipper domain (bZIP) proteins required for proper asexual development and gliotoxin production.
作者：Xiao Peng;Shin KwangSoo;Wang TianHong;Yu JaeHyuk
作者机构：[Xiao, P] State Key Laboratory of Microbial Technology, Shandong University, Jinan, Shandong, China, Departments of Bacteriology and Genetics, Univers 更多
通讯作者地址：[Yu, JH]Univ Wisconsin, Dept Bacteriol, 1550 Linden Dr, Madison, WI 53706 USA.
关键词：aspergillosis;human diseases;pathogenesis;Aspergillus fumigatus;Trichocomaceae;Eurotiales;Eurotiomycetes;Pezizomycotina;Ascomycota;fungi;eukaryotes;fungus
摘要：The opportunistic human pathogen Aspergillus fumigatus reproduces asexually by forming a massive number of mitospores called conidia. In this study, we characterize the upstream developmental regulator A. fumigatus flbB (AfuflbB). Northern blotting and cDNA analyses reveal that AfuflbB produces two transcripts predicted to encode two basic leucine zipper domain (bZIP) polypeptides, AfuFlbB beta (420 amino acids [aa]) and AfuFlbB alpha (390 aa). The deletion of AfuflbB results in delayed/reduced sporulation, precocious cell death, the lack of conidiophore development in liquid submerged culture, altered expression of AfubrlA and AfuabaA, and blocked production of gliotoxin. While introduction of the wild-type (WT) AfuflbB allele fully complemented these defects, disruption of the ATG start codon for either one of the AfuFlbB polypeptides leads to a partial complementation, indicating the need of both polypeptides for WT levels of asexual development and gliotoxin biogenesis. Consistent with this, Aspergillus nidulans flbB+ encoding one polypeptide (426 aa) partially complements the AfuflbB null mutation. The presence of 0.6 M KCl in liquid submerged culture suppresses the defects caused by the lack of one, but not both, of the AfuFlbB polypeptides, suggesting a genetic prerequisite for AfuFlbB in A. fumigatus development. Finally, Northern blot analyses reveal that both AfuflbB and AfuflbE are necessary for expression of AfuflbD, suggesting that FlbD functions downstream of FlbB/FlbE in aspergilli.