Gatherar I M, Pollerman S, Dunn-Coleman N, Turner G
Department Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield, England, S10 2TN, UK.
Fungal Genet Biol. 2004 Apr;41(4):463-71. doi: 10.1016/j.fgb.2003.12.004.
We have cloned a novel gene, hbrB, by complementation of a temperature sensitive hyperbranching (hbr) mutant of Aspergillus nidulans. The mutant, hbrB3, exhibits hyperseptation and shows a marked increase in hyphal branching at the restrictive temperature. A genomic library incorporating the AMA1 sequence, which confers autonomous replication on the plasmid, was used to clone the gene. Co-ordinate loss of the complementing plasmid and wild type phenotype was shown. The 847 amino acid predicted product of the hbrB gene shows significant identities with Neurospora crassa and Aspergillus fumigatus hypothetical proteins but no other obvious relative outside the filamentous fungi. The gene was placed under control of the alcA promoter and downregulation resulted in a loss of polarity phenotype. These results suggest that A. nidulans hbrB is specific to filamentous fungi and is essential for hyphal growth and polarity. Index descriptors: Aspergillus nidulans; branching; hbrB; hyphal growth and polarity
我们通过对构巢曲霉温度敏感型超分支（hbr）突变体进行互补克隆了一个新基因hbrB。该突变体hbrB3表现出过度分隔，并且在限制温度下菌丝分支显著增加。利用包含AMA1序列（该序列赋予质粒自主复制能力）的基因组文库来克隆该基因。结果表明互补质粒和野生型表型协同丢失。hbrB基因预测的847个氨基酸产物与粗糙脉孢菌和烟曲霉的假定蛋白具有显著同源性，但在丝状真菌之外没有其他明显的亲缘关系。该基因置于alcA启动子的控制之下，下调表达导致极性表型丧失。这些结果表明构巢曲霉hbrB是丝状真菌特有的，对菌丝生长和极性至关重要。索引描述符：构巢曲霉；分支；hbrB；菌丝生长和极性
